Side windows are fogged up

Replace them with single pane windows. No matter what, dual panes will leak after a few years, so you're right back where you started. Single panes, have nearly the same insulation factor, because they're thicker. Do a search, there's some companies the will fix your dual or replace them with single pane. Talk to them and see what they recommend. I've had about 1/2 the dual panes in my RV repaired, but never again, they'll get replaced with single pane. Everyone worries about the insulation factor of single panes/ My answer is, your windshield probably has more area then all the other windows in your RV combined. Guess what, your windshield is single pane.