Tonijim,
You are going in a 32' class "C" which fit in nearly all CG sites in the area and and also in Michigan State Park CG's. Will it be only adults or will you have kids with you as that can make a difference as to which of the so many attractions and places you may prefer to visit. All are very child and adult friendly and are totally safe for all ages. Can't speak for most private CG's site sizes as we rarely stay at them but most are very family friendly too.
However, bear in mind that RV'ing and camping is extremely popular in Michigan as there are a few thousand CG's in the state and over a hundred thousand campsites in Michigan and most are heavily used. Reservations are suggested for most popular areas and basically required for about 1/4 of the best of the many CG's, especially on the west side along Lake Michigan in July and August and you'll see the reason why! What things, activities, experience do you like to do as that will be a big help in answering your request? It's not expensive by any stretch to enjoy a delightful couple weeks in the SBNL area or in West Michigan and I realize costs are very important to most. We can say that because we are a little familiar with MA and the high costs etc there as our Son and wife lived west of Boston when he was an engineer at Bose Corp on Bose Mountain in Famingham abd we've been there several times and all over New England. Also have family in East Longmeadow and Marblehead.
