Thanks, it's reassuring. It's tight to get access to the rear of the WH, but I've previously changed the water pump which is even further in behind the WH, just need to crawl in the basement and do some contortions.
Doing some research, I'm pretty well talked into going with a tankless unit from Atwood. Only a couple hundred more (also on Amazon, get much of my stuff there too). We normally don't out-run the 12 gallon unit, but we do have a lot of "waiting for it to heat up" since we camp at a variety of locations (bad electric, boondock, etc.) where we can't/won't leave the regular WH on all day.
I think the "instant hot water" will do us more good than the downsides I've read about on the tankless units. Would be nice to have electric and propane instead of just propane with the tankless, but if we don't have to wait for the water to heat up, the electric option isn't that important to us (other than "free hot water" at some of the locations we camp).