Although I can't give you good route advice, you mentioned Walmart. Not all Walmart stores allow overnight parking. You might look at a cellphone app called ONP Walmart. Another option is the website RV Parky. They both give good info on Walmarts (although the information between the two may be conflicting). Rural Walmarts and those further away from popular travel destinations are more apt to allow night parking. Other options are some casinos, Cracker Barrel restaurants and some travel centers. Just be a courteous guest.
Dan & Christine (and Molly)
2015 GMC Sierra 4WD Crew Cab Short Bed with Max Trailer Pkg
2015 Jayco White Hawk 27 DSRL