"Take-apart-able" portable generator box -- suggestions?

Problem is if you want to run the generator under it...you have conflicting desires of getting it good airflow and sound deadening.

If you just want a cover, we have a fixed one out of 1/2 inch plywood (sealed with epoxy) that takes up no extra space, is light and a simple solution...but you can't run the generator.

Anything you can run the generator under needs waterproofing and good airflow both for engine intake and cooling. Piecing something together is likely going to blow your sound deadening idea.