Hey Mikhen,
I used Meguiars too and it is a good fiberglass wax. I just didn't think it lasted very long. Certainly not a year. But that may be because my fiberglass IS older and more oxidated. I believe the Mequiar's would wash off with a strong detergent such as TSP. You would be experimenting with how little preparation you can get by with and still get a good shine from Red Max. Most of us who have tried it felt ours were so far gone that a new product, not proven for RV's was worth trying. As 4x4 points out the BKF really cleans and rejuvenates the finish if it is oxidized or has surface scratches etc. We all know now that RMP is an option instead of wax. By next year we will have more data on how WELL it works. Have a great season! :)
On edit: What do you use for de-oxidation? Maybe that is the step I was missing when I was just using the wax. I think that is what the BFK does, and maybe it is recommended because it is cheaper than other de-oxidizers?