ken56,
Only an issue getting reservations in the extremely popular Lake Michigan on the Lakeshore CG's like Grand Haven, Holland, Ludington, sometimes in Hoffmaster and Silver Lake State Parks. These CG's are usually booked full within a day or less when you are able to even reserve. Weekends are busier than weekdays like any where else. These Lake Michigan Beach CG's are of course extremely popular as is the area. However there are so many other good CG's near the Big lake in all these areas to also choose from and reservations are not that hard to get unless you wait until the week you leave home to reserve. In 55 years of RV'ing we have only gotten reservations 4 times total and never went without a place the camp yet. We live at Grand Haven and have for over 77 years so we know.
You have to remember that there are more than a couple dozen summer festivals in the communities along the lakeshore so of course the CG's would all be full for them for the festival time. Grand Haven U.S. Coast Guard national Festival annually has well more than 350,000 attending during the 10 day long festival so all the couple dozen local regional CG's are packed full for it. Also on the 3 major holidays weekends too. Must be a real reason for having such a high attendance each year for 96 years now!?
Usual camping season each year in Michigan is from late April until after Halloween but many CG's are open year around. Even Tahquamenon Falls State Park in the northern Upper Peninsula close to Lake Superior Lower falls CG is always open with kept plowed sites as are the snowmobiles staging parking areas for camping. Electric on all winter long at the open SP CG's. Some State Park CG's in the Lower Peninsula are too. Lots of snowmobilers, skiers, snowshoe, and just regular campers are in the CG's We have so many time in the past too before wife became disabled.
Beautiful in the winter and RV's have furnaces, are insulated (some better than others), have fresh water tanks and holding tanks too. That's all it takes and is why RV's even have the liquid tanks! We always used our large 5 gal Thetford Porta Potti as they can be dumped about anywhere in toilets or pit toilets. Don't need to take a 10 minute long shower each in the RV in winter but rather a short shower etc and most tanks will last well over a week or even more. Would be a tad chilly camping in a tent though...
A superb CC LB 4X4, GM HD Diesel, airbags, Rancho's, lots more
Lance Legend TC 11' 4", loaded including 3400 PP generator and my deluxe 2' X 7' rear porch
29 ft Carriage Carri-lite 5'er - a specially built gem
A like new '07 Sunline Solaris 26' TT