Pilot/Flying J usually have a separate area for campers. It is usually near the front on the restaurant side of the stores in most I have seen. I think most would feel safe parking there. In my opinion it is safer than a rest area or other truck stops that do not make provisions for RV's.
Just remember, stay in as much light as you can for safety and watch your surroundings. If you do not feel safe move to another area or move on down the road if you are not exhausted. Trust your gut when it comes to safety. If you have to pull into a rest area most now have overnight security so position yourself near where they park, without blocking their view of the rest of the stop so they don't have to move. I have even seen people introduce themselves to the security officer and let them know that they are sleeping for a few hours, it provides a better feeling for some.
If you have never spent the night next to an idling semi with the reefer kicking on and off you probably wont get much rest in an ordinary truck stop anyway.
I travel alone 99% of the time and sleep in my trailer each night. A little planning goes along way. Myself I prefer it a little darker as my laser sight shows up better,,, I would not spend a night in most truck stops, rest areas without my trusty sidekick loaded and waiting, but that is me.