I've seen stuff in Oklahoma and Missouri. (In fact, my rule for 40 out there is the same as all the northern routes through the Midwest. KEEP DRIVING) - but I've never seen any issues in the SW or mountain west. (I've never tried to overnight at a "truck stop" that's actually an urban station, though. )
A few bucks with a shower wouldn't be awful, but if I go back the the stuff east of the Rockies again I'll probably use one of the chain apps and make sure I know where I'm staying.
Personally, I prefer truck stops. Any Walmart lot that has more than 3 or 4 obvious RVs in it I am going to get panhandlers, "socialized" by people a little bit less sober than myself... Rest stops on the open interstate tend to be okay for bathrooms, but amazingly overlit and sometimes... Pretty drama. (Last night south of wickenburg, there was a group of 3 cars cooking and shooting juice in the bathroom. )
The trucks and trains and highway sounds don't bother me at a truck stop. Maybe I adapted from time in service, maybe I just have an easygoing anxiety system, or maybe I'm half deaf from decades of patrol aircraft. Either way, I like truck stops.
And I think they are just a touch safer