I just left my weekly breakfast at the CB on Mallory Lane. You won’t find a much safer location. It’s in the middle of a nice suburban retail district. When I arrive at 7 am on Fridays I do at times see an RV or two in the rear lot. I’d call to ensure they allow it first, though, as Brentwood does tend to have restrictive laws. If not allowed there, try calling the Sam’s Club on Mallory Lane, which is in Franklin. I see RV’s there quite often.
There is also a CB in Franklin on Franklin Commons Ct. if they allow overnight parking that would be a relatively safe spot, and is right off the highway.
I’d avoid the one on Sidco Dr for an overnight.