I used to own 1972 Prevost conversion that sit 8 years before I bought it and then in my 12 years of ownership it would sit for 2 years.
The only thing I did was taking engine batteries home and keep them under battery maintainer unless I put them for different use.
Golf-cart batteries would keep charge (when disconnected) for a year just fine.
Gasoline engines are a bit different story as evaporating gasoline can leave gunk behind, but FI should be safe for couple of years if the tank is pressurized.
RV owners are always paranoid about their vehicle maintenance.
Me? Even I am not a farmer, I like the farmer's idea about winterizing their equipment.
"disconnect the battery, put coffee can over the exhaust and walk away"