Bathroom on the road?

We always do. Even when we pull into rest areas we still use the RV toilet. Cleaner and safer. Plus we can grab some food and eat in there if needed.

Yes, as long as you have some water in the tank to flush with go ahead and use it. I use mine like that all the time.

One of the best things about towing (or driving) an RV is our ability to use our bathroom any time the need arises. As long as you can reach the bathroom w/o opening the slide you can use it any where you stop.

Even when we stop for gas or resupply of snacks we use our own bathroom.

Absolutely, you need to make sure you have water in your fresh water tank and you'll need to turn on the water pump but since the pump runs on 12V you should be able to use it at any time. We used ours instead of going into the facilities at rest stops on the 2 week 3k miles trip we got back from last weekend because of the pandemic. In the past we never traveled with water because of the low cargo capacity of our trailer, but desperate times means we probably pushed our weight limit.

We use our bathroom all the time on the road. Just find a wide space in the road and pull over. Just make sure you have some water in your tank.