Where to train in a wetsuit?

I've signed up for 70.3 Wisconsin, which is on June 11th. I'm expecting it to be wetsuit legal. I recently bought a used wetsuit from a friend (good quality, was only used a few times and replaced because he lost weight training and it got to large for him). I've done a few wetsuit races before with rented wetsuits and they have not gone well - the swim portion bordered on diastrous.

Now, I'm not a bad swimmer. I swam competitvely for 8 years, so the stroke is mostly there (I have some bad habits I'm currently working on correcting). But I'm not used to swimming in a wetsuit. The constriction on my chest makes me feel like I can't get enough air, which leads me to using breaststroke instead of freestyle.

Obviously, I know this is a problem and want to work on it before my race. However, I live in northwestern Missouri and most of the lakes in my area won't be open for public access until Memorial Day weekend (and even that's not guaranteed if the water is cold or of poor quality). I don't want to train in my wetsuit in the pool because I don't want the chlorine to eat away at the suit (and I also don't want to overheat). Does anyone have any ideas or suggestions on where I can train in a wetsuit prior to my race? Am I going to have to suck it up and use it in the pool and just wash it out really really well afterwards?