Deleted rear wiper and motor and plugged the hole today. Don't know if it will help my gas mileage, but I never used it and reduced a little weight.
Here is a better shot of my coroplast side skirts. I think I'll keep the wheel covers solid black.
I like the pipe insulation grille block idea. Easy install and remove. My water temperature hasn't gone above 185 F so far, so I may block a little of the lower grille until the heat of the South arrives.
Side note: I was running a couple of errands today and getting 47 mpg for the trip. Either I'm getting much better at hypermiling or these mods are helping. Maybe both.