Atc camper - replace canvas top with hard top

Hi, we have a very old ATC camper which travels as a trailer and when camping the beds push out and the canvas top goes up like a tent.

We have had pieces replaced on the canvas but what we'd really like to do is have the top part replaced with a solid top.

Could anyone direct me please to a website or such where someone has done this?

Thanks in advance for any help.