After reading this thread for sometime, and living in the KC burbs for the last 30 years, I decided to look up all these unsafe Walmart locations. Using the Walmart app, I pulled about 20 stores in the KC area. The only one in KC, MO is East of Koffman stadium on I-70 between loops 435 & 470 which should be a safe part of town. Just South of there is one in Raytown which I would not shop or stay in because I personally wouldn't go to Raytown for any reason.
KC, KS shows one Walmart on the West side at loop 435 and Parallel, which is just North of I-70. This is the NASCAR track destination location complete with Nebraska Furniture, Cabellas (free overnight parking, water and dump) KC soccer stadium and tons of food and entertainment venues. I'm overnighting at Cabellas, givin the choice.
Every other Walmart the app pulled up is in the suburbs and, in my opinion, in absolutely safe locations. However, I doubt that you would be allowed to overnight at many, if any, of the locations due to local ordinances. Make sure you call the store manager before you arrive at any of them.
A call to Cabellas is not necessary because they designed their Free RV parking lot, water and dump stations for all the "Freeloaders" who want to stop and stay for awhile. However, you may want to check the NASCAR schedule of KC racing events before showing up.