You will have plenty of time to manually focus and a hand-held meter can be better than using TTL metering, particularly using a spot meter. I wouldn't worry about either auto-focus or in-camera metering for medium format.
Simple to use / load, high quality build, reasonably priced, refurbished to great condition. Fully manual but images come out very sharp. I bought an Isolette II and couldn't be happier for $125.00. The guy is very helpful and corresponds very well with any questions. He will probably have whatever you need, email him. Certo6 - Vintage Folding Cameras: Agfa Isolette
If you want something that is handholdable, look into Hasselblad like a 500 C/M, super duper Zeiss lenses. For architecture, I recommend you look into a Fujifilm GX680III. It is a monster of a camera, really design for studio work and needs to be tripoded. But, it has built in tilts and swings for 'proper' architecture. If you are serious, then go for the Fuji ... If you're just testing the waters ... Buy something like JC recommended and get a little wet. Fuji makes a number of very good rangefinder MF cameras and Fuji lenses are exceptional.