it really is quite the conundrum you have going on there, Skot. One needs electricity and compressed air to powder coat, plain and simple. How to do that in a structure where you are limited to both, I do not know. You may indeed have to use only one device at a time until you figure out the best way to do things. Can you rob power from somebody elses' side?
(just kidding... that's a fast way to make enemies). By all means experiment with smaller items to get the "touch". I warn you now though.... just because the parts are small doesn't lessen the bug that gets planted for powder coating anything. As a matter of fact... it gets worse due to the fact that you want to see "bigger and better" examples of what you can do. Try doing smaller parts ( fishing reels and hinges,etc) and using a toaster oven for the time being. Then if things look like they might be to your liking I'm sure during all of this you'll figure out a way to gleen the resources you need in that garage. Keep us posted on this one.... it's interesting, that's for sure.