WOW! Those were a lot of questions...
Let's see what I can come up with for ya.
What to wear?
Well, I wear tri shorts with a tri top. It goes from water to bike to run. I don't ever change clothes. I don't like wearing shorts that tight in public... but shoot, I'm racing. If they don't like, they don't have to look.
When I go to wetsuit swims... I will wear my tri shorts and top under my wetsuit.
Where will I put my wetsuit? I always have a towel under my bike with all my stuff on it. I suspect my wetsuit will go on this towel. I think my bag might take up too much space in the transition area.
Tri Wetsuits (these are made specifically for swimming- other wetsuits may not have the flexibility needed in the shoulders and other areas for swimming). Well, that's were it gets confusing as far as I am concerned. I honestly just went for one that cost around $400, and figured I couldn't go wrong. Luckily I found a 2006 2XU Elite that was $475 marked down to $330.
Here is generally how a race will go:
1) Setup your transition area. You will lay out your biking shoes, socks, race belt with number, running shoes, bike helmet and maybe glasses. It's best to put all of these items on a towel under your bike. I also put a small hand towel with my stuff, so I can dry and clean my feet out of the water.
2) You put on your wetsuit (if it's wetsuit legal), and then start when you swim wave starts.
3) Out of the water you go to the transition area and put on your biking shoes and helmet,and race belt with your number on it. Here is where I use the small hand towel, so I don't have stuff stuck to my feet and inside my socks for the rest of the bike and run.
4) Take your bike to the red line, mount and ride.
5) After you have completed the ride, dismount at the red line, and go to your transition area. Take off your helmet, and your bike shoes. Put on your running shoes and go.
6) Run and then cross the finish line.
What's the most tiring thing or is it simply the combination of things? 12 miles on the bike is nothing and three miles of jogging/running/walking is not much either. I'm thinking it has to be the swimming??
Swimming can really tire people out, if they have a poor stroke and are not trained for it. The swim won't win the race, but you can drain yourself in the swim enough to not finish the race.
The bike is pretty easy... but going from biking to running... is a challenge.
This is why when you train for your tri, you will need to do some bricks. A brick workout is when you bike and then run immediately afterwards. This will prepare you for the "legs of jello" for the first 1/2 mile or so.
Well, good luck! And who knows... you might actually like it and want to do another one again?
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"