If it runs, and you can/want to drive it - drive it!
Tackle the mechanical restoration stuff a sub-project at a time (to minimize down time) and drive it a bit here and there. When it's time to paint it, then be prepared to not be able to drive it for quite awhile.
If you're wanting to do a full-on, tear it all apart and replace everything that's wrong with it including sheet metal, then do yourself a favor and tear it down to absolutely nothing, media blast it and coat with epoxy primer, keep & catalog the good parts (or the ones that need minor restoration and/or are irreplaceable), make a list of the new stuff you'll need, and begin with rust abatement. Be prepared to have a long process of simply working on the car, though.
Don't do a 'phased' approach like I did - you'll find things that need attention as you go along, which will slow down the process when it would've been smarter to just tear the whole thing apart and concentrate on one thing at a time.
Whatever you decide, take your time and have fun. ::thumb::