Well, the best fitness sport, including for shooting training, is swimming. It's perfect cardiovascular exercise, does not abuse your skeleton, strengthens all your muscles including the "core" muscles, increases flexibility and improves your timing. Unfortunately, it's a highly technical activity and a beginner who doesn't use a coach is probably just wasting time.
Re: goal setting, I think the best thing for me is to plan training sessions, look at all the individual matches on the calendar to put them into context with the training and with the one or two other things we must deal with in life (making a living...) My goal is to see shot execution improve. I think having a particular score as a goal would be counterproductive for me. The better shooters are different.
