We have purchased the portable fencing panels so we can keep our dogs in an area around the RV without being on the leash the whole time. And yes, we will be outside with them when they are in the pen...
I run the fencing to the steps and then I bungee cord a boogie board under the steps, to block that escape route. Has worked well for years. Some parks do not allow the fencing. If it's an issue, they will usually come by and tell you. We started when snowbirding in our RV. It didn't seem right to keep our puppies on a leash all winter. And like above, we never leave them out there alone.