On those occasions where I've gone sightseeing not only did I have room to park the MH but the towed as well.. There is one vacant front facing seat for darling daughter to ride in or.. You might check with the child seat makers to see if there are any that can be side rated.
Most folks forget that these seats need to protect in a "T" bone collision as well where you are the top of the T so they do offer some side impact protection, what I do not know is... how much.
Drive: Towing a towed, With a good size house (Mine is 38 foot 3 slides) 13 wide when set up) I get about 8MPG... Parked, My towed, last refill I had some issues with leaking fuel, not sure how much leaked, MPG was 26 though (I did not leak much it seems) (Or it might not have been gasoline that was leaking, Might have been rain water that somehow got into an unusual spot I did not check the liquid) Back to topic, Some cars now days get 30-40-more-e, Miles per gallon..
Decent pick up with a decent size 5er.. again 8MPG towing, perhaps sixteen to 20 bobtail. (not towing).
Motorhome: The worst thing for a motor vehicle is to do nothing, Just sit there and .. well... rust. They like to be driven from time to time, Mine hits the road (normally) every 1-2 weeks, Though when I checked into the body shop (Hospital) It sat for 3-4 a couple times last fall. (I checked out and hit the road with it, then checked cat into it's body shop (Vet) for a day, more road, more doctors for me, and finally my 800 mile migration a few weeks later than planned for the winter).
Trailers.. Well if they sit too long you need to re-tire them (This is true of the Motor home too) but that and re-packing of the wheel bearings, Check the water heater, furnace and fridge for nesting critters and do a general PM on them and body wash and wax.. just about covers it.
And you need to do those things parked or rolling rolling camping.