first,remove the upper trim from the tub edge, then remove the front panel. unscrew the drain from under the tub, remove screws from upper edge of tub, then you can remove the tub. First check your pex tube connectors in the wall between the kitchen and bath, their should be an access panel in the lower kitchen cabnet, check lines under pressure to see if they leak, if you have never changed these on a 77 , I would change all of them in your camper, should be 7 of them, if one is dried out , they all are. it might also be easier to remove the toilet before removeing the tub for more room. if the water was sitting under the tub for a while, you may need to change the wood floor under the tub, its not that hard and then you will have peace of mind knowing that it is done correctly. best of luck with your project, mine took me about 3 days of my spare time