Hey Johnlin--
1. ASK. Most docs that I've talked to are really receptive to having someone shadow them. I asked my family doc if he knew anyone I could shadow, and he suggested that I shadow him, and it was an unbelievable experience. I was incredibly lucky b/c my doc just happens to be a preceptor for Duke and UNC first-year med students, so he did the same things with me that he would do with an med student. He also told other docs that I was shadowing him, and they asked me if I wanted to shadow them! Unfortunately, I don't have the time to do this, but it was incredible. All you have to do is ask-- ask your doctor, or find a specialist you're interested in and if they aren't available to have you shadow them, then they probably could refer you to someone.
2. Leadership for a post-bacc...hmmm. Honestly, while leadership is nice, I don't think it's a requirement (I'll refrain from getting on my "there is no set check list or forumla for acceptance" soap box this time. 😉). In my opinion (for what it's worth), get involved with something that interests you, regardless of whether or not it's medically related. You'll be a much more interesting candidate if you're enthusiastic about your activities rather than just going through the motions. If you're dead-set on finding some leadership activities, try mentoring, tutoring, volunteering with your church (or whatever-- just an example) youth group, volunteering with a local civic group-- whatever. Once again, the important thing is to find something you're genuinely interested in. It makes you happier, and you'll be a better leader.
Best of luck!