Having spent many years working on and off on my 67 resto, I'll jump in here with a few thoughts:
1) Welder--unless you're going to put this on a rotisserie, you're not going to want a TIG. Crawling around under a car to weld is hard enough, without trying to hold the wand with one hand, the wire with the other, and peddling with the third...(or your foot). You're going to want to be able to one-hand it with a MIG gun.
2) FWIW, I have a $300, 90a flux-core only bottleless box that's done all the welding I've needed from it. I got it from my motor pool mechanics as a retirement gift, and I've done everything from thin gauge body metal to the spring perches on my axles (8.8 swap). Since it's what I learned on, I don't know how much better it would be with a bottle, and the portability can't be beat.
3) Take a look at the Dynacorn one-piece complete floors. If you've got much cancer at all (and from what I saw, yours isn't that bad compared to what I had to deal with), it's a nice swap.
4) I'm sure you know by now that all your front-end parts are available, including the frame rails. Just be careful, if you're going to replace them, that you don't strip everything off forward of the firewall. You're going to need some parts in there to get the new rails aligned in all three dimensions.
5) Take your time planning. Keeps you from having to do things twice (like I did with my brakes, and will be doing with front
suspension and steering).
Let me know if I can help, or answer any questions! Oh, yeah, and have fun. When you're so PO'ed you're ready to throw something, call it a night.