By far one of the best #Overland modifications has been removing the rear seat and replaced with a metal platform.
05/20/2021 UPDATE: This platform is available for purchase at PriusOverlanding.com
This is a prototype of a rear seat replacement that will be available for the Gen3 Prius. Are interested in one, click the parts request link in the site menu to receive more details.
The best part is I can remove the platform, place the seatback in, and the four-seat bolts in less than 15 minutes without a power tool.

I placed some auto carpet on the floor. After installing sound deadening material and a layer of insulation, it feels really comfortable now without the exposed metal.

I gained a tremendous amount of cargo space and even lost a few pounds losing the seats.
Next, I will make custom storage containers that have bottoms molded to the curvature of the floor. Stay tuned…