We never have reservations when traveling around the USA, Canada, or even Alaska during our over 54 years of extensive RV'ing. Whether, traveling in a TC, TT, 5th wheel, Class B - C or our big A's in the past. Why are so many RV'ers so particular as to where they stop for overnighting? They aren't going to buy the CG but just staying for maybe 10 - 14 hours of sleeping and eating and sometimes using the sewer, or electric, or water, or maybe even the dump station and then be gone and on the road again! Big deal??? All you get is a receipt (if charged a fee) to add to your pile of them.
Yes, perhaps to wanting a certain CG or spot for a week etc stay at a very popular final destination sometimes. Maybe usually but certainly not always. CG's usually fill up more often on weekends or during popular local events or over the 3 holidays weekends but seldom are full on the other 5 days of the week.
having an option A, B, and C is smart also as most all events are local oriented so there is usually some open sites not that far away and RV's have or are mounted on wheels that turn to get you to where there's a site open. Even if not, you still and gobs of choices and Cracker Barrel is just one of the many. The list is so long and you are only staying there for a few hours anyway. We do use Cracker Barrels a lot as our relaxing dinner is only feet away and maybe a nice breakfast in the morning also. Love them!
Never once have we gone without or driven an extra few miles to find a decent safe place to overnight most with some to full hookups with just us 2 traveling or when we took an additional 2-7 adults or kids with us anywhere in the land connected USA or Canada.
Passport America is another huge help/choice as there are nearly 2,000 CG's to choose from. We have been PA members since their beginning and also use them often.