Since I hate unfinished posts when I'm researching, this is to close this one out. I followed the steps and suggestions outlined in the thread. Pretty happy with the outcome, but I did learn a few things:
1. You guys weren't kidding about cleaning the metal. Wherever I had issues with a weld sticking it was because there was a little dirt or rust still left behind. Another tip from my dad was to clean the metal somewhere on the body for the welding clamp. I tried just sticking it to a dirty part and there wasn't enough conductivity to get a clean weld.
2. Weld Thru primer is good for lap joins, but its not the best conductor for welding. I had more luck with bare metal and only used the weld thru where I had to.
3. Don't weld an inside corner haha. It's very hard to grind it flat and clean afterward. This is what I should have done...
4. After its all buttoned up, use a body sealer to fill any left over gaps. I also used body sealer around the edge of inside the cab. It will be covered by carpet eventually, but really seals things nicely to keep water and crap out of the cab.
5. A hammer and dolly are fantastic tools for stress relief and making things fit
