Mike,
If you don't try to fix everything, but will focus on a few specific models, you should be able to pick up the proper repair and service manuals, maybe on e-bay, but more likely from Finger Lakes Photo Books or Craig Camera. Issues of the SPT Journal and the Camera Craftsman magazine are also good sources of how-to information. Just be aware that some 'repair manuals' are nothing more than detailed parts lists with a short note in the front to take things apart in the number order presented in each of the diagrams. The National Camera manuals specific to a particular model are quite detailed and useful. If you are working on the Minolta SRT series, get the repair manual on the SRT 101 first, as the body casting was the same on all 21 models in the SRT series (and thus all the sub-assemblies fit together the same way). HTH.
Mike M.