Hi Grant,
I essentially have two wooden sheds attached together with a doorway between them, only one roof comes off though and this is hinged. The roof has a light weight wooden frame with light corrugated plastic on the top. It is easy to open and I can be up and ready in only a few minutes!
I have to say I don’t get a lot of problem with condensation in there, and I myself prefer it to a dome. You can see all of the sky (so you can spot any meteors) and of course you don’t have to keep turning the dome! The floor is concrete and it houses my 8 inch reflector- an arrangement I have had for over a decade and which I find very satisfactory!
Best wishes,
-Paul