I would prefer to stay mechanical lift. Trying to do a manual lift when the total inside height collapsed is under 4' would be awkward for an older person. The top will have some wood structure in it. There will be two solar panels on top,a roof vent, maybe a set of roof rails. The rails would be for show and breakup the side outline of the panels from a distance. I wouldn't use the rails for any hauling.
On a rough guess with the panels and vent the top assy will come in around #100. The ply will be 1/4" inside and out. The closest place with 1/8" is 65 miles one way. The prices were almost the same as the 1/4" I can by local. My local lumber yard has 1/4 luan with exterior glue. It looks a lot better than the box stores.
Now those hinged sides in that second link to the small popup looked promising. I hadn't thought of that.