The 20% rule applies:
Use a tow/haul vehicle with at least 20% tow or haul capacity to spare.
Run a tire arrangement with 20% extra capacity.
Use hitches with 20% capacity to spare.
Dream of all the space you will ever need in the RV and add 20% before you buy.
Add 20% to the weight of any truck camper you look at.
Take all fuel economy claims and reduce them by 20%.
Multiply all pickup truck OEM b.s. claims by 20%
Save 20%/yr of age by buying gently used if you don't have to have a toilet no one has sat on.
Add at least 20% to your gotta get there trip time pressure and enjoy your new rv. No make that 40%...
enjoy