Excluding the topic of if the 25 ft Winnebago is right for you, or not, and if it has any major hidden defects.
I live in Louisiana and have a 28 ft class A motorhome which I bought in 2016, and have since driven about 20,000 miles most of which has been in the western US without a TOAD car, including Yellowstone. At 28 ft (29'5" bumper to bumper) there are certainly limitations on parking, but most of the time it is not too bad, and of course would be somewhat easier in a 25 ft coach. A standard full size parking space, like one might find at a big box store is 22 ft long, with a motorhome in this size range, means you need to find a place with 2 spaced end to end, or you need to be able to back in and overhang the curb in a single parking space. Also due to width unless you can pull straight forward out of the parking space, you are likely to need a 2x2 grid of open parking spaces in order to not hit the neighboring cars due to off tracking and tail swing. When you make a right turn, all that length sticking out behind the rear axle will swing left, if motorhome drivers fail to account for this thing tend to get hit, usually gas pumps, and curbs when parallel parking.
Now down to what this means in practical terms, rarely have I had to miss anything I really wanted to see, as in most towns I can find a place to park within reasonable walking distance (a couple of blocks). There are of course exceptions to this, I recall one small town in I think Wyoming where I wanted to stop to see some small museum, but could not find parking anywhere, all the downtown parking was curb front diagonal parking, most of the secondary parallel streets were too narrow for curb front parking, etc. I did eventually find some parallel parking one block off the main street, but this was nearly 1/3 mile from the museum, and I just did not feel it was worth that long of walk.
There are also destinations where it just is not worth the hassle of finding parking, or moving the RV every day, at some of these places we have rented a car (Branson, MO, and Fredericksburg, TX), used public transportation (Eureka Springs, AR, and Grand Canyon NP, shuttle bus route that picked up at campground both places) or called an Uber (Sante Fe, NM).
I will try to attach a couple of photos of my coach backed into single parking spaces overhanging a curb at roadside attractions on travel days. (Ok, that did not work, but I did get 1 picture, at the Blue Bell Ice Cream Factory visitor center in Brenham, TX, note it looks like there are a lot of parking spaces to choose from, but in reality there were only a couple I could back into here due to overhanging limbs)
p.s. you mention driving into town to eat and shop, while on the road on travel days we will sometimes stop and eat at a restaurant, in the course of our travels we have stopped and ate at several casual dining places located next to big box store parking lots that we have parked in, as well as several Cracker Barrel's as they tend to have RV parking, I have even stopped at an Arby's which had its own stand alone parking lot, though this was not a typical Arby's as it had a fairly larger parking area in the rear, and its parking lot connected to a budget motel so I knew I could get out once I pulled in. Once we are at an RV park and set up, we will rarely disconnect until it is time to move to the next destination, this excludes places like inside Yellowstone. Often we will fix our own dinner, or sometimes there is a cafe at the RV park, or within easy walking distance where we will eat. (scouting out parking ahead of time using google satellite and street view can be a big help)