My 5vr and both truck campers had filon. I hand wax twice a year with paste wax and easily clean in between with a damp, not wet, microfiber cloth. When damp wiping I turn the cloth very frequently and change cloths often. On the 5vr I would go thru a couple dozen wash cloth size microfibers. The caps get waxed four times a year and I've never had a problem cleaning bugs off of them, even during Love Bug season in the Deep South.
I sold the first truck camper after 10 years of traveling back and forth across the country and it looked as good as the day we bought it.