Ceiling fans. I noticed this past spring when we were RV shopping that a number of the very high 5th wheels had ceiling fans.
It may or may not be a factor for you.
We ended up with a TT and there are some significant differences in heights between various make/models. Arched models give some nice breathing room.
With ducted A/C it doesn't take up more than about 1" of headroom.
Bed lengths can be a challenge. Be sure to check they are sufficient and comfortable for you.
Looks like others have covered the external height, but at 6'5" I thought internal heights might be of interest for you, too.
Good luck!