New headliner insulation for some areas

We're trying a different product for headliner insulation in the salon and head. It's a moisture-proof polyurethane that's thin, flexible, and sold in large white rolls as a flooring underlayment in the hardware store (Lowe's, at least). The immediate advantages are that it's easy and fast to put up, covering the ugly scarred expanse of ceiling left from removal of the prior headliner; with spray adhesive (3M number 90). Also, any moisture won't soak into it. We'll see how it performs over time. Next, we'll reseat all items such as window screws on the upper deck using sealant in order to prevent or minimize leaks. We already started that with sealant at the base of the mast yesterday. Then, maybe next weekend or otherwise the one after that, we can install the new headliner fabric in the main berth and salon. We'll test to see if we can use the spray adhesive (it's quite strong), or must use the Contact Cement (gelled product in a can, brushed on thickly), for the headliner fabric. A different approach will be used in the head. I want to find a good vinyl to cover the insulation-covered areas (mostly Fiberglas exterior walls), or maybe a flexible hard surface that's easy to clean and will stand up to showering. Then, for the inside face of the entry wall, white paint (or hardboard), also impervious to shower spray. And for the nice wood wall behind the sink, several coats of polyurethane for a waterproof (at least water resistant) attractive wood surface.