We have traveled across the country from and to Alaska several times. We have stayed in Walmart, pull off places, municipal parks, etc.
I don't let the noise of Walmart or any other place bother me. I have only felt unsafe once while camping and it was in a private, paid for campground. Neighbors were drunk and fighting.
Usually when we stay at Walmart or similar, we use the "fingers" that we cary with us and a plastic shopping bag or two and pick up junk that others have left on the ground. Often when others see us doing it they join in. We have met several other RVers in Walmart and truck stops that have become friends with distances.
I met one woman who was staying at Walmart - had been there a week. Her DH became ill. She was given a spot to plug in, had awning and lawn chair out with their permission.
One such store near us has a license as a campground. Allows for 3 day (can be more) camping. Has free water and dumpstation.
Pull-offs can be tricky. When there is a sign "No camping" we don't (if we can see the sign). We have never been bothered by LE, but left once because we didn't feel comfy about another vehicle that pulled in after us. Especially when the beer cans were tossed out the windows.
We travel Route 2 most of the time across the country and there are several free and low cost campgrounds along that way. We do utilize canpgrounds when we aren't trying to get somewhere quickly.
WE often try to do "pick up" at pull off places along the AK highway. It seems that when we do pull off, someone else has stayed and left their garbage - and often other stuff - for us to clean up.
We are looking forward to our East bound trip again this summer and will be enjoying staying at all kinds of campgrounds as well as Walmart, truck stops, and pull off places along the way.