Suggestions for fantasy/medieval terrain kits for kids

My daughters have been liking playing with my terrain, I was looking to get them some easier kits on the cheaper end to build and paint(partially as a decoy from my more fragile setups). Unfortunately the two places I had used in the past that were budget oriented have closed, so I figured I'd come here for suggestions to see what you guys would use.

More specific additional info:
I've tried doing more pure scratchbuild projects with them before, but it ends up with them distracted and me doing all the work which is a big contributor to looking for easy assembly. Popsicle sticks, foam, etc is going to take more of my time than theirs and likely end up broken. So something appropriate for girls in the single digit age range that are capable of cutting and gluing paper dolls, but not using heat knives, box cutters, etc. MDF is a possibility if it doesn't have loads of fiddly bits. Plastic punch card with plastic corners/stands could work. Probably want to avoid papercraft kits because of durability.

I appreciate any guidance, thank you!