I've been in a similar position. I still haven't finished the job yet! But here's some information that might encourage you
http://www.peachparts.com/shopforum/body-repair-restoration/309677-fun-games-welding-sheet-metal-arc-welder-learning-weld.html
Once you've got the hang of your buzz box you'll then need to to start learning again on the car! Welding in different positions is a new skill.
Essentially welding is all about penetration - you want to have had enough fusion / melting through out the joint but not so much that you melt it all away.
If anything the job that you want to go and do on the car is ideal. There's lots of space to reach the area where you need to weld - though you need to remove that electrical wiring well away from the area you are going to fix.
The next problem you'll have is bashin' metal. You'll want to make some new pieces that fit I guess...
...if you leave great big gaps between new metal and old you'll struggle with any welder but particularly a stick welder to fill them.
Go to
MetalMeet - for Metalshaping Enthusiasts & Professional Metalshapers for tips on how to shape and weld metal.