We camped in a pop-up with 2 kids. They were about 10 and 11 (a little older than yours, maybe). But, from the time the kids were old enough to walk, we started teaching them to help with everything. Our kids were doing their own laundry by the time they were 5. They needed a watchful eye, but they did it. They learned how to add the soap, turn on the machine, and even sort the clothing out.
When they got older, the turned into slobs! I think that's just natural for kids, and we went through some challenges.
But, when camping, everyone jumped in and helped, packing and unpacking, and setting up camp and tearing down camp. It was a group effort. The time it took to teach the kids and discipline them paid off in the long run.
(something must have worked, my daughter now has 4 kids herself, all under 6 years old, now she REALLY understand why we did what we did back then).
The best thing you can do to make it easier is to plan it out a little smarter. Remember, some items can remain in the camper, you don't have to drag them back and forth. Kids don't need near as many clothes as you may think. Keep one set of clothes if you go somewhere nice. Keep a couple sets for them to play in. If they get dirty, let them wear them again anyway. This reduces laundry. The kids are not going to DIE because they were the same pants 2 days in a row!
Let the kids select their favorite toys. Let the kids carry their own toys back and forth loading and unloading. If they don't bring it, or fuss about packing it ... well ... don't go back and get it yourself. Don't take it if they don't load it! And things YOU think the kids need to play with are not necessarily the the things THEY really want to play with. Let them make their own choices. And there again, if they fail to do so, they take nothing, or only what they DO select. They'll learn real fast and next time they WILL take it!
When returning home, get things ready to unload before leaving the campground. Gather laundry in one or 2 bags, get your perishable food items in containers that are easy to transport back to the house ... AND I don't think you mentioned anything about your husband, BUT ... nothing says HE can't help too!
Bottom line, make it a family effort, and teach the kids (and the husband) EVERYONE has to help! Or simply stay home one time and protest! They'll get the idea REAL fast!