Electrical From Scratch

OK. 30 amp load center is typical. This is fed with a 30 amp shore power cord (10AWG), available at most Walmarts or big box stores. You probably don't have the correct male plug in your "odds and ends". If you're building this with conventional residential bits, you'll probably end up with a 75 amp (or so) loadcenter. The load center will have spaces for more than two breakers. You'll want one 30 amp single for the main breaker and you can decide how many more you'll need but breaking out the distribution into a few branches will work best.

This is my pet peeve: a "plug" is the male end of a cord. A "receptacle" or an "outlet" is a device that accepts a plug. It's just like "linoleum" isn't sheet vinyl flooring or "that board" isn't a sill plate in a stud-framed wall.