That hub looks a lot like mine. It's filthy so odds are the bearings haven't been serviced regularly, so check them.
The rim, I'm sure you are aware, isn't suitable for rim brakes. You'll probably need new spokes to build up with a different rim unless you find one with the same "ERD" measurement.
I still haven't had a go at wheel building. It's just so easy to find good used wheels that I have been able to avoid it so far.