Doug,
We have stayed in Loops 300, 400, 500 and 800. We like 500 the best. I would say no to the 300 loop because it is better suited to small trailers and motorhomes. I had to have a shoehorn and Crisco to get the bus into the site. If you are taking a dog these will be your likely choices. If no dog, I personally like the 700 loop because it is most open and closest to the boat to the Magic Kingdom followed by the 600 loop because of its proximity to the pool and outdoor movie. We have always run our generator in the rest areas in Mississippi and Florida and have never had a problem. Both Mississippi and Florida have nightime security at the rest areas.
Loc