Peterborough will have a 2 loop swim and a mass start, so expect more congestion and rough housing at the start, significantly longer bike and run (only 500m more in the swim, but bike and run are more than double compared to Olympic distance), need to eat and drink more on bike, dealing with stiffness/tightness from riding on aerobars longer, getting lonely on bike when field gets stretched out, losing concentration/daydreaming on bike and not working hard enough.
PREPARING FOR A LONGER RACE
I was recently asked a number of questions related to building up to a longer race, in particular a Half Ironman race, and how it differs from an Olympic distance race. I have included the questions and answers below for those who may be looking beyond their first triathlon.
Take your time building up to the distance. I also recommend some over-distance rides. I think 120km is a good distance to build up to. If you can do a century ride (100 miles) that's even better. It will make the 90km feel much shorter. Also be able to run more than the run distance in training. Do some long brick workouts where you bike 90-100km and then run for 20-30 minutes right away to get a feel for bike to run transitions. I also advocate weight training, especially for the legs, because it makes you a stronger cyclist and your bike to run transitions become much easier.
An Ironman (IM) requires 3-4 weeks of tapering whereas a Half you should consider 1-2 weeks. It all depends on your fitness level and your goals. If the half is just preparation for a full IM the taper is less important. Be sure to be well rested. It's better to be 10% under-trained than 1% over-trained. I'd go with a 2 week taper if you are trying to peak for the race.
There are lots of options here. Many people just bike in their bathing suit, which isn't as uncomfortable as one might first imagine. Men need to finish the race wearing a shirt of some sort, but women can race in just a bathing suit if they like. If you are a little more modest than that, you can take time to put on a pair of shorts after the swim (either cycling or running) and a top but be aware that there are no changing tents so anything you put on will go over what you are already wearing. If you are wearing a wetsuit, you should wear whatever you will biking in under the wetsuit to save time and make transition easier.
Drink lots in the 2-3 days leading up to the race and be sure to increase your salt intake so that you retain some of that water. Salt tablets during the race are helpful too. Read my article on Hyponatremia in the Sport Health Section of Xtri.com or on my website at SpinalHealth.net. I am a columnist for that magazine and the article on salt deficiency can really help you. I don't carbo load at all, I just eat regular meals. I might eat a bit earlier the night before a race, but I don't change much in the diet.
You don't need to wear one. One year at Peterborough, the water was so warm I thought we shouldn't have been allowed to wear them, but they let us. You float more and swim faster in a good wetsuit, plus you can wear your race clothes underneath so transitions are faster. The water will be warm in July, but if you have a triathlon wetsuit you gain a definite advantage. A windsurfing wetsuit, in contrast, is not designed for swimming and may slow you down.
I am very comfortable in my swim suit on the bike. It is padded and I don't find I chafe on the seat or anything. I was surprised how comfy I was the first time I biked in a tri bathing suit. However, I don't race like that anymore. There are some very comfortable multisport shorts on the market which are more comfortable than cycling shorts on the bike and you can run in them. If you want to wear cycling shorts, just wear them under the wetsuit. Wear everything you will bike in (other than shoes/socks/helmet, etc.) under the wetsuit to save time. If you wear a bathing suit under the cycling shorts, you can whip the cycling shorts off after the bike and put on running shorts for the run if necessary. I don't recommend trying to put on dry clothing when you are wet from the swim - it really slows you down.
Most "sport" sunblocks are good in that regard. I have used Coppertone Sport, President's Choice Sport, Banana Boat Sport, and Ironman Sunblock and all work very well. They are sweat and water proof.
This is what I do and recommend to others. I eat an Energy Bar (or maybe 2) right when I get up, about 3 or more hours before race start. After that, I don't eat any solid foods. I have a liquid recovery drink after the bar, it's got carbs and protein in it and makes a good pre-race meal. I use Endurox R4, but anything will do. Stay away from those meal replacement drinks in a can - too high in sugar and bad fats. The idea being the solid food can be digested if you give it enough time and then the liquids are easy to digest given less time. If you eat solid food on the bike, blood has to go to the stomach to digest it whereas liquids and gels can be absorbed. You want blood in your muscles, not your gut. So, solid food early (pre-race), then right away into a liquid 'meal'. I'll drink water or Gatorade on the way to the race, and on the bike for a Half IM I carry sports drink, water, and gels. Or I'll carry one bottle with my recovery drink in it and that replaces the need for any bars on the bike. Wash a gel down with water because using sports drink will create a concentrated sugar solution in your gut which may upset it. They have 2 water bottle exchanges (I think) on the bike, where I get fresh water. I usually have a JetStream bottle in my handlebars with sports drink, a large bottle behind my seat with sports drink, and a small water bottle which I toss and replace at an exchange point. If you wear a cycling shirt with pockets in the back you can carry gels in there, or get a gel flask that clips/straps to your frame. A flask holds 5 gels. What I have done in the past and it works well is to tape the tops of some PowerGels to my frame. The tape was across the level where you tear it off, so when I wanted one I pulled it and it opened right away. Chase it down with water. Do not overeat on the bike. I've seen people DNF because they ate 5 PowerBars on the bike and got sick. In training, I can do 120km rides off of sports drinks and recovery drinks alone, so I know in a race I don't need more than that. People always overeat and then have stomach aches. That's why over distance rides are good - you can work out your nutritional needs because the over distance part translates a bit into what you may need on the run. You can use a fanny pack if you like - lots of people do - but taping to the frame is easy and fast. Drink lots, but if the weather is cool don't overdrink because you'll become hyponatremic (see my article for details)
Bottle exchanges as outlined above, maybe they give out a gel but don't count on it. Nature is your toilet - pick a tree. They may have some toilets at the exchange stations, but I never bother with them. Pull over to pee if you need to, or if you are in a hurry, pee on the bike. The fast guys all do - they can't be bothered to stop.
None on the route to my knowledge.
It is much more efficient to pedal with stiff soled bike shoes. If you don't have 'em, you have to pedal in running shoes I guess. You can buy Pedal Platforms for biking in running shoes, but good cycling shoes and cleats are pretty much a must for comfortable cycling.
Training should take care of that (brick workouts). It is something you do get used to with enough practice. Otherwise, try to get up and stretch your back and legs as you are nearing the bike finish.
Some stops have PowerGels, but not all. And if they run out you're out of luck if you were counting on them. Carry some in a shirt pocket (a good tri shirt will have back pockets) or in a fanny pack. Stops generally have water, Gatorade, and some have flat cola. If you drink cola, you get a sugar and caffeine rush which can pull you out of a bonk but you have to keep drinking it once you start. I recommend waiting until the 2nd half of the run before drinking cola, and not at all if you don't need it. Gels are a good idea, but don't overdo it. Eat one as you approach an aid station and then take some water. Once again, you need to practice to know how much you need to eat.
Some I think, but lots of trees :) Learning to pee while running will save you some time, if you're in a hurry.
Yeah, they sweep the course for roadkill :) Just kidding; you shouldn't need it if you're preparing well in advance. Usually an ambulance or Subaru with a bike rack picks up mechanical failures.
Course closes at 3:30pm, so it's basically 7.5 hours, which should be plenty for most athletes.
If it's hot, the run can be oppressive as there isn't much shelter. ALWAYS wear a hat on the run - it helps keep sweat out your eyes and the sun, too. If you have a hat and can get some ice at an aid station, put it in your hat to cool your head. Dumping too much water on yourself can make clothing heavy and shoes wet, thereby making you grumpy. Better to drink it than wear it. Know your salt requirements. People who have stomach cramps, muscle cramps, vomiting, bloating, etc. are all hyponatremic (low salt levels). It's the main reason people don't complete full IM races. Let me know if you have any more questions. Good luck!!