Wow...nice to see a young guy so enthusiastic!
The floor: youth and enthusiasm will overcome any difficulties with this. I've been looking at it for my '62 Suburban too. I was thinking about making a bead roller with a very deep throat to roll beads into the new metal floor and use the existing supports the truck already has.
Heater: Get the Delux heater and mount it. I've been told it'll be a small improvement over the one that only mounts under the dash. If you have a big heater box on the firewall already, you've got the Delux.
Sound deadening/insulation will also be a very big help.
On my '62, I'm going to install an underseat heater from a '54-'56 Buick/Pontiac. It's a round heater core in a housing, with a fan on it that sits under the driver's seat and aims up. The housing also diverts some heat across to under the passenger front seat, and out to the foot area of the driver's and rear seat. The can for the fan's motor pokes down through the floor, and the heater hoses also go through the floor. Probably not a HUGE help, but I'm sure it will be welcome.
You're gonna be out swingin' in the breeze for Suburban-specific patch panels for the quarters, rear doors (or tail gate) and tail panel area. Also, the wheel housings are Suburban-specific. They're rounded, while the regular trucks are more angular. You'll have to fab some pieces, and if you can find a really nice fleetside bed, you can probably make your own patch panels for the quarters.
Patches or new stampings are made for everything ahead of the firewall, except the hood itself. Doors will interchange with pick-ups, so find some good doors. All the door hardware and internals are available new.
Get a bottle on the welder and go to town. I JUST hooked mine bottle up, after trying for 10 years to get a welder. I'm 36, and just welded up the first thing in my own garage (some misc. holes in the firewall previous owners decided needed to be there). You're a step ahead of me--you've already to the welder! Took me almost 20 years from where you are now.
Good luck.
-Brad
