Waterproofing a Trail Mini bathroom?

I have the Trail Mini 18L. I know most owners have the larger ones, but if anyone has any info or input on possibly applying some kind of waterproofing product to the interior walls of the wet bath please let me know. The bath is tiny and once you close the shower curtain on all four sides, it sticks to you. Plus, there is only one holder for the sprayer and it's down below waist level. So my goal is to waterproof the door and mirror walls so I only need the curtain over the toilet and sink plus add an additional sprayer holder above the mirror. Thanks!