Other than repacking the bearings, I wouldn't pay anyone for anything you've listed above. However, if you have mobility issues, it would be helpful to have someone else wash and wax the camper. You know your camper better than anyone and use it daily. If something is not working correct, you'll know it in a heart beat. If something doesn't seem right, check it out yourself first. Use your common sense, think it through, and if THAT item just doesn't seem right, then get THAT one item looked at by someone else, if that be a shop or a mobile tech.
Check the caulkin a couple times a year yourself. If you see changes occuring, you will know that. If you start seeing cracks in the calking, just clean off the old a little and overlay with new. The most important thing you can possibly do, is inspect the roof as often as possible. After that, wheel bearings and tires dry rot, and then everything else is secondary for life-longevity of the camper.
Water heater? as stated above, drain it and flush it out, replace anode rod if it's worn down, put the anode rod back in and don't worry about it for a while. I drain mine often, and we use it full time, but we are not "full timers" (on the road).
