RE: A few questions from a new guy
IMHO you would be doing yourself a favor by joining a club, getting a high wing trainer and get very comfprtable with it. Once that is done get your self a low wing tail dragger sport plane and get comfortable with it. I don't know about your P-51 and have never flown a P-51 but I have a few warbirds, pretty much all I have and each flies a bit differently. Most have a heavier wing loading and require a bit more skill flying. Warbirds are not a good starting point and with a 20 year break you are closer to starting then an accomplished pilot. Glad to have you as a member of the hobby!