Your looking at roughly $500 for a basic setup, for gas consider spending quite a bit more... That $500 doesn't include all the other gizomos that make your flying experience, in my opinion, more enjoyable.

That will get you a basic 4 channel transmitter, a basic trainer and a basic engine.

Call me crazy but I would say a .40 sized trainer is the best place to start. I would recommend the SIg Kadet LT-40 myself.

In terms of relating your sailing and kiting experience, I'm sorry to say that I think they will offer you very little edge while starting (just my opinion though).

I terms of durability most trainers are designed to take some abuse based on the nature of what they are intent for... to learn. That said, no plane will handling all damage a student can throw at it. The only plane I've seen that might come close is the Aircore Trainer. Then again it flies like a brick and I think there tough to find.

Finally, different people learn at diferent speeds, but I would think that you'll need more then a couple of days a month to learn. Also, if you're gonna teach yourself (which I don't think I'm alone in saying, will be very tough to do) please do it away from crowded areas.