I Need a checklist

In terms of a checklist, you'll quickly enough develop your own (usually by means of experience in forgetting things). I use a system I think I read about here somewhere: I have a bag of clothespins with checklist items written on them, and start by clipping them to the sun visor and then unclipping them and returning them to the bag as I do the items before leaving (or decide they are inapplicable at the time).

Here are all the pins I currently have, in no particular order; your checklist items will probably be a bit different:
Vacuum
Sweep (linoleum)
Shake Rugs
Oil (check engine oil level)
Counters (free of stuff that might fall off)
Water Hose
Bedroom Blinds (raised or secured in clips so they don't rattle about)
Trash
Close Windows
Bedroom Windows (I'm not sure why I have them separately...)
Electric
Sewer (disconnect if full hookup, dump if tanks are full and there's a dump station)
Welcome Mat (don't leave behind)
Water Fill
Ceiling Vents
Awning
TV Antenna
Compartments (outside storage compartments closed and latched)
Clean Windshield
Tire PSI
Water Heater
Water Pump (I generally travel with it off--not really necessary to do so)
Count Noses
Prayer

(I don't have any slideouts to worry about in my motorhome.)

For storage at home, it's only necessary to empty the water tank and drain the lines (and winterize!) if there will be freezing weather. Some would suggest it's a good idea if the motorhome will be sitting for quite some time so you don't have water sitting around and maybe having stuff grow in it, and I wouldn't argue against them.

Turning off the propane is not necessary, though it's also not a problem. The only times it's necessary to shut off the propane at the tank are when refilling the tank--and the employees at the fill station should do it then--or when driving on certain bridges or tunnels where propane is permitted but must be turned off, such as the Chesapeake Bay Bridge/Tunnel. When turning the propane on or off, take care to fully close or open the valve; they may leak if left in a halfway open position.

It is never necessary in general use to bleed/drain the propane lines.

The 12V disconnect switch is of limited usefulness. If you have 120V power where you have the motorhome parked, plug it in and leave the 12V switch in the connected position so that the converter can keep the batteries charged up. If you don't have 120V power, it's better to disconnect the batteries (remove the ground lead from the negative terminal) as often there are a few items that are powered regardless of the disconnect switch setting like the propane alarm, radio memory, etc., and these can drain the batteries over the course of time. Batteries do self-discharge even when disconnected, but the rate at which this happens is quite dependent on the temperatures; in freezing weather, it's very slow indeed, and not a concern over several months if they are fully charged to begin with. In hot weather, a few weeks can lead to a significant amount of self-discharge. Even a fairly modest solar setup can be a big help here.

Setting some mousetraps is a good idea when the motorhome is in storage. Keeping it free of food that would attract mice is also wise.