IMHO there is a best and safest way to store an RV, especially handling of wet cell batteries. Then there is a 'get me by' approach and of course the wrong way. The first will preserve your batteries for 10 years. The second, which depends, may be 3-5 years and the later maybe a year.
Living in Mi all my life I have dealt with dead batteries more times then I care to count. Over this time I have developed my own approach, which is if stored over a month or so, they go on a trickle charger, which is no job for me. A bit aggressive I know, but just how I do it.
I'm lucky enough to be able to keep my RVs at home and they've stayed plugged in 24/7.
If I had to store in a no power remote location over the winter, the batteries would get pulled, gasoline treated and run through engine and genny. The trip to storage would be long enough to make sure everything reached operating temps, including genny. I would not return until spring or until I needed it.
Needing to run the engine is a fallacy. Cold starting an engine 4-5 times during the winter does more harm than once in the spring. Any engine mfgr, especially diesel, will tell you do not start the engine unless you are going to drive it long enough to get everything up to operating temps and drive an additional 30 mins or so. This expels the condensation out of the exaust system, engine oil, trans fluid, ect.
So, do I want to take the batteries home and go back when I need the coach, or do I want to go the storage yard 4-5 times over the winter, perhaps wading through feet of snow to charge my batteries?
The thing here is there are so many variables between RVers. Storing in AZ is going to be different than ND. I am still strong and mobile, my batteries weigh 66lbs. Some folks batteries weight 160lbs and weigh more than they do
All an OP can do here is wade through all the opinions and make a choice that fits their personal situation or the one that makes more sence to them. Some do well and some don't, but it's never a life changer
AGMs - abosultely don't need them, therefore the additional cost serves me zero purpose. Not so for some folks in their situation.