One of the first projects we did was install some sound deadening to help reduce the road noise and also add a bit of insulation. We’ll eventually add more insulation, but for now this is a good “first step.”
The barrier we choose was Hush Mat: https://smile.amazon.com/gp/product/B001VKO8WE/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
The 30 pack was just the right amount to cover all the main areas in the back of the van. It cuts easily with a knife and while it’s pretty sticky and has sharp corners it is pretty easy to install.
We used this roller to help make sure there weren’t any bubbles while installing it. https://smile.amazon.com/gp/product/B085Y239HX/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1