Hi guys, thanks for all of your suggestions! I was able to fix the rear turn signal -- there was just a connection loose.
I didn't have as much luck with the headlight, however. I took it off to look at it, and I immediately noticed that there was a wire that wasn't connected. Let me preface this again by saying that I have pretty much ZERO mechanical experience, so I really didn't know much about what I was looking at. However, there was a green/gold (I'm red-green color blind, so sometimes colors look the same) wire that was not attached. I think it had a copper end to it, and it looked like it was supposed to be plugged into another wire of the same color with a similar head, which was surrounded by a clear plastic-rubber housing. I plugged it in thinking that would solve the problem -- but no luck. All the other wires appear to be attached and okay.
So I'm not really sure what could be causing the headlight to not work. The two smaller lights above the headlight work just fine. Leonard suggested checking for a good ground -- I'm just not sure how to do that. I could probably do it if I knew what to look for, but I just have no idea. By the way, Leonard -- are you the Enfield owner in Salina, KS? I ran across your profile on this site and sent you an email. I'm a new Enfield owner just outside of Wichita, KS and was wondering if there were any other owners in the surrounding areas, and was wondering and hoping there might be some sort of gathering or group.
Thanks again guys for the support! I hope I get this headlight bug worked out real soon...