Packing cubes. Packing cubes. Packing cubes.
Seriously, get yourselves packing cubes.
What you're doing now:
Pull clean clothes out of drawers and closets, pack into boxes, then unpack from boxes and put in cupboards.
What you could be doing:
Pull clean clothes out of drawers and closers, pack into cubes, plop cubes in cupboards.
Color coordinate cubes for each family member. Even little ones can remember their stuff is in the pink cube. Cubes come in all sorts of sizes so you can fit most anything.
If you can, at the beginning of the season, pull a selection of "getting ready to retire" play clothes for each kid. Put those in the cubes and store them in the RV. Those become the season's camping clothes.
If you can't do that, then let the kids prepare their own clothes. Tell them to select 5 undies, 3 shorts, etc. (whatever they will need) and lay them on the bed. Then you come in and do a final check before they pack them in their cubes. The kids will enjoy helping, they'll get help with their numbers, and you don't have to do as much. If their packing is sloppy, who cares - you're camping.
Get yourself a hanging fabric clothes hamper. Each night when the kids change into their jammies, any clothes that can't be worn again go in the hamper. When you get home, just grab the hamper and dump it in the washing machine. You may need a couple of them for your family. I hang mine in the shower stall. You could hang them in the closet or even outside at the campsite - they're just old clothes.
Food: as others say, keep staples in the RV for the season. Canned soups, beans, etc., can all stay without issue. For boxed dry goods (pancake mix, cream of wheat, etc.), transfer the contents to tupperware containers and then cut out the instructions and duct tape them to the container. Use tupperware to hold snacks, etc. The tupperware will help prevent bugs/rodents.
Maintain soap, toothpaste, toothbrushes, shampoos, etc., in the RV. At the end of each trip, just check the levels and replace/refill if needed. When you're packing for a trip, no need to think about it.
For medications, have a small packing cube ready to go that will fit them. Just drop the bottles in and take it the the RV. When you get home, just bring the cube into the house.
Electronics, etc. - use a packing cube to store all the cords, plugs, earphones, etc. Easy to keep track of everything. Extra batteries - packing cube. Crayons, pens, etc. - packing cube. Use iron on transfers to identify contents - have each kid make a picture of the contents (e.g., a picture of a crayon) onto the transfer paper, then cut it out and iron it onto the cube.
In case you didn't figure it out - packing cubes. :) :) :)