I have been wanting to learn how to do back flips and 360's for a while, does anyone have any ideas for a jump that would be ideal for those types of tricks?
When I was a kid we used to take ramps out to our local lake and set up at the boat launch, it was a ton of fun and you could try soooooo many tricks. Just really hard on the bike !!!!
For backflips, see if you can get access to a trampoline, build yourself a trampoline bike frame from PVC, and practice. Probably helps to get backflips by yourself first. Alternatively, bmx+pool noodles+wodden ramp + sufficiently deep water also works.
For 360s, just a matter of trying it and falling every time until that first time you land it.