A truck camper is a very compact RV and makes it easy to get to out of the way locations. However there are not many places to easily attach bikes to the RV. You can mount a front hitch or have a rear hitch extension and probably a superhitch to support it. Or you can somehow attach the bikes to the RV itself. These will all work and there are pros and cons. I chose to make a mount that sits on the dinette itself.
A blanket is placed under the rear wheels when moving and the bikes tied down under the table to stop them from moving.
The mount was already made as I use it in the back of my Xterra to keep bikes inside the vehicle. This keeps them clean and somewhat protected from theft. It is a piece of 3/8ths plywood and some fork mounts from Rocky Mounts. This is an equivalent product from Thule. There are many different fork mounts for different styles of bike forks and axles. Note that the fork mounts are placed at slight angles. This allow for different handle bar arrangements to fit together before it might be necessary to loosen the bars.
A couple of holes drilled through the seat deck and into the seat support as well as the bike rack plywood allow some bolts of the correct length to hold the mounts to the seat support so that nothing moves. On the road, nothing moves and nothing touches the walls of the camper or the door of the bathroom.