To answer your question on the trampoline topic - Absolutely.
Get a rope, make a handle (or use a spare one if you have it) and get used to spins and passing the handle. I also got an old skate deck and glued some shoes to it to get used to the feeling of a board on your feet (if you put some cloth tape on the bottom it doesn't slide around and you feel more stable. Learn to spin 180's both ways, then progress to 360's then 540s etc. Learn to jump high then spin blind 180 on the way down or at the last second using the rope. Learn to grab the board while spinning (and also when jumping). There's lost of good advice in the forums I'm sure - have a search!
I lived away from somewhere with water for a couple of years (although I got out every couple of weekends) and the trampoline kept me sane (and I'll admit, it's a lot of fun
). You'll be surprised what you pick up, even in your 30's (I landed my first double S bend when I was ~34, Whirly's & Crow mobes at 36)