..... I have been noodling this all day!.....
I didn't know you like to go catch catfish with your hands !!!!
Great to re-use old stuff. People used to get on my dad about all the "junk" he collected, saved my butt more than once he has!
There is a local garage I dive by, they do a ot of auto painting. Tey have a big roll up door, but then they put in a wood frame with clear ribbed plastic roofing material. They are bale to let light in but stil have a door.
I like your idea of being able to move it away. Make it wide enough so you can put some eyebolts in and attach to walls to it won't blow away on ya, but easily removed.