I was thinking about what you want while browsing the forum but came back too late to edit my post, adding to what i said i thought about a design i tried to sketch it but it just didn’t look right and i think it may just make it seem more confusing. So i’ll just try and explain it the best i can !
If you had a 2x4 (base) with a 2x4 (middle) directly on top and then a 1x2 (top) level.
The base level would be pretty hard to clean as there would be no way of getting in, you wouldn’t want to have an opening door at the front as you’d need to have beams going across width ways (beams being two grids wide) to support the middle level. The beams would rest on each side of the cage meaning the two 4 grid long sides wouldn’t be moveable as they’d be providing support.
But you could create a door system on one of shorter of the sides (on the base) that is just 2 grids wide, so basically at the end. That would allow you to slide out the correx tray, change it and then slide it back in and close the door. (If you have the space of course) You would have to decide on some sort of latch system to close the doors over maybe binder clips ?
But basically on top of this base you could just build your normal 2x4 with a 1x2 hay loft
Recommendation for ramps would be square guttering with carpet tiles as these provide grip and safety sides and are easy to clean.
*When i say beams i literally just mean bits of wood that go across to take some of the weight My wood is about the thickness of grid squares and just slide in the grids easily and do a great job at keeping everything sturdy
I hope this helps, if it doesn’t make sense i can try and make a better diagram
