Part of the consideration is how easily accessible the rig is. My TT is stashed quite a ways from the Austin city limits, so access to it tends to be limited. In there, I keep some nonperishable items, some water bottles, a change of clothes or two, and bedding.
Once I jump to a "B", and it is ready in the driveway, that makes it a lot easier to move food between it and the house. Some non-perishable reserve food (and water) goes without saying. However, having some refrigerated foods (frozen dinners) is always useful. This way, a trip out doesn't have to involve a pit stop by a grocery store beforehand.
In any case, I always recommend storing anything food/drink related in a tightly fitting container (metal is best, plastic is OK). Last year, I used a container for some cereal items, and even now, the contents are still edible because of the airtight lid. The containers not just keep things from getting stale, but keep the critters out, and if there is a freeze and a liquid gets out, it still is contained in something, so it doesn't wind up spilling over a shelf.
Other than food, I like having a few complete changes of clothes.
Electronics-wise, I keep a small external (1.2 amp-hours to 2.0 amp-hours) battery for charging USB stuff. I also keep a tablet that has its own cellular connection, so I can read a book if need be.
After buying the MH, I may end up buying a small cargo trailer for behind it, partially as a way to mark a site as reserved, but as something to have at the ready for longer trips, (or, God forbid, evacuations). The cargo trailer would also be stocked with items, but planned around long term stays/boondocks, and would carry additional supplies (TruFuel containers, water, food, camp stove, bedding, clothing, and so on.) The advantage of this setup is the ability to pile in and take off for a few days, at a moment's notice. If an evacuation is called or there is a disaster, the trailer gets hitched, and comes the ability for longer term outings.
