We had to replace the glass on our old camper after it got busted. I also rebuilt the doors on that camper so I have a pretty good idea how they are made.
If your camper has the typical solidy window with just the white trim around it, just take the trim off from the inside. Have some (or do it with the door open) hold the trim on the outside when you get ready to take the last screw out as it may fall out of the door. Take the glass to your local glass shop have them cut & tint a piece to the same size. The window isn't glued in or anything, it is only held in by the little clips on the inside of the plastic rim and the screws pinching it together. I've actually thought about pulling ours out and tinting the frosted glass - especially in the bathroom.