OK, the idea is moving along a bit. I'm thinking of using the 6" f/10 refractor on a Gerrish mount. The telescope OTA would be carried out and slid onto it's cradle before each observing session, and removed afterwards. The "observatory" building itself won't even require a roof that opens. The only opening besides the entry door will be the portal that the OTA fills when installed, parallel to the earth's rotational axis. It will have it's own door when the telescope is absent. I have a 9" minor-axis elliptical flat that is perfect for this application, so I can go with a larger OTA in the future, if desired. The flat would probably be removed when not in use, as well. The RA drive will be inside the building. DEC motion will be achieved by a long shaft running parallel to the OTA, with the motor (or hand wheel, I haven't decided yet) inside the building as well. So I still have to carry out an OTA and flat, but no mount. And I can switch on the heat while I'm installing the optics so it's warm and toasty when I sit down to observe. Stay tuned.