What’s wrong with them laying in that closet? Can you make that an acceptable nesting location for you? Probably not or you would not be asking but I’ll ask silly questions.
Is this just one egg or have they been laying there for a while? It’s not that unusual for a pullet to drop her first few eggs wherever she happens to be but once she gains control of the process she will return to the same nest every time. So if this is regular, she is committed to that spot.
If you block that area off there are different things that could happen. They might move to the nests, they might start laying outside somewhere, or they might lay somewhere else in the camper, probably near that closet. They are living animals, no one can tell you what they will do for sure.
So what can you do? Try closing off the closet and see what happens. You could easily get lucky.
As Aart suggested, can you leave them locked in the camper with that closet closed and force them to find another nest in the camper. You could easily get lucky.
This one is more involved. If you can get them used to laying in a mobile nest (maybe a cardboard box with bedding in it) where they are now laying, then you can try slowly moving that mobile nest toward the main nests. Just move it a foot or so every couple of days so they keep using it. Then when you get to the nest area, take the mobile nest away and see if they make the switch. Close off the closet of course. I’ve never tried this one myself but some people on this forum say they have had success doing this.
I’ve used this trick several times. I made some of my nests so I can lock a hen in there if I wish. When I catch a hen laying where I don’t want her to, I move her to the nest and lock her in until she lays her egg, then let her out. That normally takes about a half hour, but I have had some go three hours. I usually only have to do this once but I occasionally get one that is stubborn about it.
Good luck with this. It can get a bit frustrating.