I would study as much as you can about the different types of chopper. What I mean is, even though I am a relative newcomer to the scene I can now spot some parts on bikes that are advertised as "original" restored to notice wrong pedals, decals, grips, chain wheel, front wheel, brake pulls etc. Decide on what model you want (Tall Frame, Sprint, High Back, "standard" 3 speed, up-turned cleat, crossover, Mk1 or Mk2 etc.) Check out the prices they are going for. You have a healthy budget and should get something really nice for your money. I have found there is far more to this iconic bike than meets the eye.