>> would you bother fixing, or start looking for a doner van to swap all of
the good stuff into? <<

From an emotional point of view, I really hate to see another Vanagon taken
off the road. Unless you are in CA there really aren't allot around anymore.

Now, logically speaking, you have now removed the van from the location that
was causing the rust. That's a big step so I would think that fixing what
rust you have is going to be easier than converting a Vanagon into a Westy.
(unless you were to start with a Westy donor).  It looks like you need to
pop out all your windows, fix the rust then put them back in. It would be a
good time for some new rubber too.

Bryan