17 year old triathlete

      Welcome, to answer a couple of your questions, for the bike I generally train different places depending on my season. For example this year my main races are both in NH so I try to ride on 102 or rt 3 because of the hills.
Crabman being in South County you won't really have to worry about hills, though it doesn't hurt to mix them in. If you live near the race I'd try to get out and ride the course, or get out on rt 1. Swim- for open water Roger Wheeler beach is very nice, I also like Carbuncle Pond and occasionally I head up to Walden Pond in MA other than that I'm usually in the pool. Running, I'm sure you've got that covered but you should try to find a place where you can leave your bike and practice transitioning from bike to run.

Nope, haven't really noticed many teenagers, I'm not generally paying attention though. 

The only club I know of in RI is Providence Triathlon team, don't know much about them.
Hope that somewhat helped.

Good luck on your race and remember to have fun!

-Dave

Hey NoLimit! Check with your local Y.  There are several that have tri training teams and you might run into high school and college runners there who are also doing tris this summer.  Good luck! 
PS I have seen many high school athletes at local tris.  They are often part of relay teams but several do the entire event as a great way to cross train.