I prep'd it with Clorox and TSP (tri-sodium-phosphate). The Clorox kills the mildew in the pores and the TSP is an excellent de-greaser.
Then I primed with two coats of white KILZ and top coated with three coats of white polyurethane enamel. The enamel was formulated for floors, but the Scamp
doesn't know the difference. It all came from the local Home Depot.
Interestingly I also bought the best brush at HD for enamel -- but found a cheap chip brush actually worked better at getting the paint into all the little depressions in the ensolite.
For ventilation I had already removed a broken top vent, so I just placed a 20 inch box fan on top of the trailer over the vacant vent.
Hope this helps.