Here is a simple mod I just did to prevent the side window curtains from deteriorating in the sun (one of ours is already falling apart). In stead of storing the unit with those curtains closed (and fully exposed to the sun), I picked up a 4' X 10' roll of window shade from Camping World:
Multi-Purpose Foil, 4' x 10' - Four Corners AO2012-003 - Window Covers - Camping World
This stuff is very easy to cut with scissors. I first cut it in half (yielding two 4' X 5' sheets) and then cut each sheet to fit the sides:
Now when the Axis is in storage (and not covered during the summer months) I'll be putting these up instead of closing the curtains.
I may end up buying a second one to make a front window cover but that shade seems to be surviving the UV pummeling its getting.