I am 6'4" and also looked at the Casita... I have full standing headroom in the galley area. After camping a few days, the comfort of being able to stand up straight is going to be worth a lot.
I think if we drove under 60 our mileage may not be too bad. Have not gone on a "trip" yet, but have pulled it up and down the Interstate going to weigh station. We are still figuring out where to put things. But it looks like there is more room than we thought.
If you consider packing for a suitcase trip staying in motels, and compare that just to the storage area under the two dinette seats, each is bigger than a suitcase. I will take the smaller one, DW will take the larger one. if it does not fit, it is not needed.
Under the built in queen is a large enough area for a good size plastic storage box plus a laundry basket. We can use that for extra blankets.
I do not plan to do much cooking in the pod, but we did order a bamboo chopping board cover for the two burner gas stove. We ordered a different one to span the sink. We have a one burner electric hotplate and plan to put that over the stove on the board to make coffee, tea, or scramble an egg.
For heaver cookinig the hotplate will move outside and plug in. This will conserve propane. If we are paying for campground hookup, why not use it.
The same line of thinking goes for a small ceramic heater.... no need to burn propane to heat this well insulated space.