Solar Fry is right. It is very easy to underestimate the amount of time and
expense that a repair project is going to take, and very easy to bite off
more than you can (or want to, or can afford to) chew.
On the other hand... I bought a MkI for $300, put another $1200 and one
year into it and sold it for what I had in it a couple of years latter.
What I got out of it was a great learning experience and a bunch of fun for
a year trying to figure out what to do and how to do it. I also was
rewarded with the pride of knowing that I had a hand in saving her from the
junk pile (she had a hole in her side from a run in with a tractor), and
that the boat I was sailing was on the water because of my work.
I learned how to: sew up a sail kit; patch a fiberglass hull so you couldn't
see the patch; install and replace hardware; replace interior wood and
flotation; buy a trailer at a bargain; build a rudder and tiller; refinish
exterior wood; paint, paint, paint; etc..
I would do it again in a second.
I guess I have just as much fun (or maybe even more) working on boats as
sailing them.
Larry