Hi there folks!
I've been hanging out around here, reading & learning. I hope, as far as the latter goes.... anyway, my first addition, just in case it may aid others.
My 18L is a '08 model, and as far as I know, the roof's never been cleaned. It wasn't in REAL bad shape, just covered with black grime/mold. I used a few small pieces of 3/4" lumber to stand/sit on as I cleaned. I used my pressure washer for the bulk of the grime and then it was good ol' elbow grease to scrub the rest off. Turned out pretty good, as the picture should show. I am not aware of any product that I may coat the aluminum with to help resist formation of the same crud, but if anyone knows, please tell me! It wasn't a huge job, so I think an annual trek onto the roof might be the ticket.
The next task was a bit more...um.... "cranial"?
I ordered a nose cone, and had it trimmed to fit (although I was off on my measurement, due to doing it myself and not compensating for the sag in the tape measure, requiring more trimming). The owner suggested using adapters (angled pieces of aluminum that are attached to the camper and then the sides of the nose cone are riveted to them), which I used. Trouble is, you have to first attach them to the camper and then do the riveting. We measured and remeasured and then just jumped in with both feet. We attached the angled aluminum to the camper and then the nose cone via tape at the top, and after making sure it was properly aligned, 3 screws at the top. Then we marked and drilled the sides, using cleco fasteners to hold the nose cone to the aluminum while doing the drilling. (It helps we both have airplane building experience!). After all the top screws were in place, I drilled for and then pulled the rivets, then started on the bottom screws. The rain has kept me from finishing the last few bottom screws and the sealant around the edges, but so far, so good.
I am looking forward to seeing if there is actually a gain in fuel mileage. Luckily, I drive frequently to a race track and back, carrying with me the identical items and load. Barring any huge wind conditions, I should get a feel for any increase on my first trip. Now to polish my camper to match...
I'll be reading some more around here to see what I should use as a wax on the fiberglass to protect it....
Thanks to all that post here, it's an invaluable source of information!