What everyone above said is correct... your "free time" is about to get nuked. Its not as bad as it sounds... but you will be rather focused on other things for the next few years. That's okay... its still a (mostly) kick ass time.
Having said that... working out to recover from stress is absolutely vital. I have never been a Ninja Turtle, but being part of a gym and working out will help you maintain balance. This is coming from both a former UPT student and a UPT IP and FLT/CC. Assuming your FLT aren't a bunch of numskulls... you may be able to "lobby" for gym time after the first portions of T-6s. If that sounds like a good idea... make sure people know their boldface. Like... perfect. Also... don't do dumb things, show up on time, yadda yadda.
TL;DR... heavy/high time commitment stuff is not very conducive during UPT. At the same time, some type of working out will most likely help you out tons.
edit: To answer your question... Laughlin had nothing outside of a local "Tae Kwan Do" gym when I was there... but that was 7 years ago. They did have crossfit when it was "the thing"... but I am not sure that is exactly what you are after. Probably same for the other bases... try google.