about every 3 weeks is good for the tires ( flat spots) when parked.
jacks and stands can be used on the chassis frame to relieve weight from the tires and suspension.
when you do run it, make sure that it is fully warm- warm enough to boil out any moisture from the oil, warm enough so that the piston rings expand and fully seal the cylinders.
short starts without a full warm up will allow byproducts of combustion to corrupt the oil, and moisture to accumulate inside the cases and exhaust due to condensation.
when storing, change the fluids first. do not let old oil sit in the motor- it contains acids and water.
our genny has a fuel petcock- we rarely use it and it is dry ( from hot and fully exercised, turn petcock off, let it run until it stalls)
I do hit the starter every couple of weeks to splash lube the motor internals
good call on running the ac- the ac refrigerant contains the lubricant, so by running the ac, you keep the lube moving through the system.
in any car it is good to run the ac once in a while- even through the winter to move the lube.
mike