Absolutely has to be bodywork/paint: This was my first foray into this whole car building thing and I had never done any. I
added,
subtracted and
things multiplied. I wanted a flared rear clip so I got some flares, during the alignment phase I over-trimmed places, during the painting phase... well, I ended up doing it twice. The biggest thing is patience to deal with it all.
Most of everything else is a mechanical assembly and someone, somewhere on this forum can point you in the proper direction. It's an amazing support group. If you're up for learning many new things, it's a fantastic project (I now own a mill, lathe, AC/DC TIG and have used them all productively for this project and others).
Another difficult thing is getting all the proper parts to work correctly with each other- from finding weatherstripping and the windshield wiper arm, to getting my gauges to work with the senders, to having proper bolts and nuts for the job. There are a number of things which I've done/bought multiple times because I thought they would work, and it turns out they didn't. But we're not building this car to save money...
In all, it's an incredible project but it's an incredible commitment. I just got mine registered (May '12) and have a whopping ~200 miles on it so far. I picked it up in Jan '07... I did have some life things happen during that span and it is my first project of this nature so the duration is understandable. Others have finished their builds in less time than it took me to prep for paint- the first time. Take the time to enjoy the build, I guarantee you will enjoy the drive!
Chris