forum newbie, trailer veteran and pink panel insulation ?

[homeonwheels]

First- I want to thank the powers for this boards existence. I have been reading tons of posts but not all [yet]. If my question was asked before- sorry.

I am doing a lot of remodeling. I took a tiny shower out of the master bedroom and I'm leaving the toilet and sink. I am taking out the corner sink and making a vanity with a table I have to spare. My idea has me pretty excited.

I have a few questions abt troubles I have run into and will post seperately.

Question w/ background:
I took out the shower, capped the waste line and water lines. They are now under the new floor. Adjacent to the shower was a large closet abt 4ft long. That wall is now abt 8ft long- counting the room I am taking from the bathroom where once was a small area to step in/out of shower. That wall was never finished for viewing, since it was in a closet. It seems to be what passed for masonboard in 1970. It is in pretty ugly shape since it had so many screws and staples in it. I put one coat of killz up just to cover it. I cleaned with tsp beforehand. This was abt a year ago. The other day, I leaned a board against the wall and after moving it I saw some of the killz just lift off the wall. So, after doing a lot of painting throughout the house, I know that that wall will need tons of prep to paint properly.

I took the closet and shower out to accommodate the head of a queen bed against that wall. The wall is an outside wall and can be quite cold.

Can I just slap up some of that pink foam panel board over the existing wall as it is? Or, do I need a barrier? The panel comes in different thicknesses and each side has a peel off piece of plastic to protect it during shipping. I was thinking that leaving the plastic on the wall side would serve as a moisture barrier. Do you think I would need to put up "lathe" strips between the wall and board? The pink stuff is paintable, cheap and comes in 4x8 sheets. I am hoping it will be a good plan since it will be pretty easy to do. I will put up panel or mason board over the pink stuff at some point. No kids will use the room, so I am not worried about the foam being dented much before that happens.

I also have in my shed, 3 boards of high moisture sheetrock. I forget the name of it. [It is not tileboard] It is really heavy. I could use that instead, but have the same questions as to mounting it. Do I need an air gap and barrier? Also, this stuff is heavy. I feel comfortable putting it in if it is resting on the floor, but all instructions say not to have it on the floor. My walls [trailer walls] don't seem strong enough to support that weight. I originally got the board to put up a new wall for the new bathroom, but have since struck a much better plan.

I have a lot of work going on and I am still flexible with most plans. I am doing all the work, slowly, and mostly by myself, but I am a 50 y/o female and have psoriatic arthritis, so there are some things that are beyond my scope. My husband can't help much.

Another issue of great consideration is the fact that the park may get eminent domained soon. We are one of a very, very few parks left [maybe 3] that were grandfathered abt 25 years ago out of the laws forbidding parks. So, we have put off a lot of repairs off thinking it would be a waste of money. We will never move this thing and there is no where to go if we could. I live in a very metro area and the city hates us. They make our lives miserable with constant harassment from the police down to city inspectors. But, things that have been put off have become necessity and I'd like to do things as cheaply, but as well as I can. I am very handy and think outside the box, so I welcome any ideas no matter how strange they may seem. For instance, I am putting up a set of folding, louvered doors for a bathroom wall. It will greatly aid air circulation and natural light in the tiny bathroom. They are wooden and quite nice. Some one was throwing them out! They will be stationary.

Sorry so long!