OP, your friend plays piano well?
Can you find a weighted piano/keyboard/controller your friend can play to create a good unquantized midi file of the piece you want recorded?
Anyway, there is a big difference between a musical piece and something quite repetitive.
That is how I would...
13MB PDF, over 400 pages. I have mixed feelings about reading this whole manual. I'm also only through 15 of the 30 videos by Kenny Gioia... it's a whole lotta' information. But I wouldn't be studying Reaper so hard if I didn't think it was worth my time. Quite the software.
I'm very...