I've traveled quite a lot with my dragon over the years, but he is an adult and doesn't have the more demanding feeding requirements of a younger dragon. I haven't had the space constraints of an RV either, so that adds another dimension. You could bring a smaller tank with you, but they are pretty heavy and not very versatile. a 20g long with a screen top would probably work and not be too tough to move around. I have a soft sided carrier that I use for travel which straps into a seatbelt. It also doubles as a secure sleeping spot for them. The need for an enclosure beyond that kind of depends on the space and what you plan to do.
You wouldn't want a dragon to roam freely around an RV if there are lots of nooks to get into that aren't easy for you to access. Using a pop up style pet playpen may be an option, but those take up quite a bit of space when they're open. The advantage is that they are lightweight and can fold up to make them very easy to store and move. I generally travel with an adjustable lamp stand, dome fixture, and either a mercury vapor bulb or just a plain halogen or incandescent flood bulb for heat during the day. I've set this up in hotel rooms and in guestrooms and it works well. Those tend to be spaces that are small and easy to secure though. Don't forget a temp gun or probe thermometer to check surface temps when you set up the lighting in a new space.
It's good to carry a bag with cleaning supplies along with you. I usually have a bag filled with vinegar spray and F10 for cleaning, a roll of paper towels, some rags, and some of the pet poop bags so I can stash the dirty towels out of smells reach until they can be thrown away. Also good to have some extra towels or small blankets for the carrier so you can just replace them if they get soiled.
I typically have a soft sided cooler with salad items, and have found that a container of black soldier fly larvae work really well for travel. I carry the 72hr reptile warmers (don't get as hot as hand warmers) to use in the winter as needed (I've never needed these during warmer months). Dragons travel well at room/car temp, but I will put one under their blanket/towel during stops for meals when the car may cool off a bit. They are also good for camping when the overnight temps drop below the 60s.
While it's certainly possible to travel with them, in this instance it might be best to find a sitter to take care of him until he gets a bit older and you've done some shorter test trips to make sure he is OK with traveling (not all of them enjoy it).
