I thas been quite a few years since I camped in the UP. At that time, many state parks did not have 30A hook ups. I know the lower peninsula had upgraded to all 30A several years ago, so I would hope the same is true in the UP.
All state parks have shower and bathroom facilities. There are a lot of state forest campgrounds which typically do NOT have water or electricity or waste dump facilities. Bathrooms may be pits toilets and they propably do not have showers.
Depending how close you are to Lake Superior, it can get quite cool at night and in the early morning, even in July. Sweat shirts and jackets are a must.