Cover

Should pods be covered using canvas type covers when not in use? Wasp like to build nest under covers. 

I bought a nice cover for mine the protect it from more sun fade. It did that, but trapped enough moisture to cause mold, like little black specks all over it.

As to wind rollover, it can be as complicated as you want, but let's not.
Take actual, total weight and apply it at the center of the axle. That weight x 1/2 of the track width (center of tire to center of tire) is the moment (torque) holding the trailer down. Say 3000 lb x 4 ft =12000 lb-ft.

Use the equation and/or table here:
https://www.engineersedge.com/civil_engineering/wind_pressure_exerted_on_vertical_wall_14014.htm
to calculate the wind pressure, then double it for suction on the leeward side.
Measure the area of the side of your pod.
Multiply the pressure times the area. Say, 31 lb/square ft x 21 sq ft x 2 = 1302 lbs.
Apply the result at the mid point between the ground and the roof. Say, 1302 lb x 4.5 feet = 5860 lb-ft. This is the wind moment.

Try several wind speeds, and make sure the weight moment exceeds the wind moment by at least 1.2x.

I don't think an R-Pod will blow over easily. I think it will slide first.

It will almost certainly slide first until it slides into something like say a curb, or the stabilizers dig in, then it can go over if the wind speed is high enough. It's important to remember that wind pressure goes up with the square of the wind speed so the overturning force in a hurricane at 120mph is 4 times what it is at 60 mph in a strong thunderstorm or tropical storm.