It depends on the individual and what they want, but that part of the country is awesome for impromptu staying in small town town parks. When I rode the Trans America on my first coast to coast we camped for free in town parks and other such places the majority of the time. We also stayed with folks who offered hospitality, stayed in a few campgrounds, slept in a couple churches who offered hospitality, and so on. We even got a room a couple times, but that was a rarity.
A good way to learn what works and what doesn't is to use one of the Adventure Cycling routes that is well established in the middle of the country as a learning tool. I figured that he ease of finding free camping in small town parks was because the trail had been blazed by others, but when I went on other rides I realized that I could do the same elsewhere where no one had blazed a trail for me.
I'd suggest using and ACA route if any suit your needs and I wouldn't plan daily mileages for each day. I never do. You will need to plan a couple days ahead at times because of long spaces between towns, but otherwise it is usually better to be flexible and ride longer when you can make good mileage and shorter when you can't. Shoot for a planned average, but not a set daily mileage. Forget riding a set daily mileage that will never happen. Spacing of services and towns, headwinds, tailwinds, climbs, descents, and weather can all drastically change your reasonable progress. Sixty miles one day may be harder than twice that another.
I find that with the ACA maps you can really do pretty much zero route planning in advance other than overall trip duration and logistics at both ends. Just pack your stuff and ride.
I should mention that all my experience is pre-covid19, but I have many times rolled into a tiny rural town, stopped in the general store, bought a few items, said something like, " I am bicycling across the US, do you think anyone will bother me if I sleep in the park tonight?", and then rolling out early in the morning. In a larger town I might ask the local cops, or at the local firehouse, or the local librarian, or ask the wait staff at the diner, or pretty much whoever I meet where I might set up my tent.