You'd be surprised to find that many truck stops [Flying J, Pilot, Love's, etc] are actually very nice.

Staff is usually friendly, they don't really fuck with you if you need to stay for an extended period of time. Also, they are a good, safe place to stop.

You can actually buy a shower from most of the truck stops along interstate as well.

If you are completely against using those resources for those days you aren't at a campground, bring::

• Paper towels/napkins
• Antibacterial Soap
• $5-$10 Pepper Spray [Seriously. Get it. Keep it on you at all times.]
• Baby Powder [You should use it on ladybits, as well as all over, especially during shark week. c: ]
• All of your normal toiletries. Toothbrush, etc.
• Towels. Four of them if possible.
• Clothespins or clips. Even string.
• Small/Travel size bottles for real shampoo/conditioner. You will get a chance to use them.
• Baby wipes, very important.

If you use tampons, they can quickly be changed using baby wipes to clean up. Use another wipe for hands, then sanitizer. Done~

If you need a second to freshen up, you can do wonders in an outdoor bathroom with a washcloth and soap. Many smaller gas stations have outdoor bathrooms. It is surprisingly easy to do so. Washing your hair in the sink isn't so bad either.

If you have to park your car to rest, do it at a truck stop, beside the trucks. Preferably, between them. Be in eye-shot of the front door to the shop. Lock your doors, then cover the windows with your towels and pins. Keeps the creepers [also: the sun] out of your windows.

Make sure your phone is charged at all times.

I can't really think of much else, but please, don't rule out those truck stops.

Sources:: I pretty much lived out of a truck for 6 months.

I hope this helps :] If you have any questions, feel free to ask.