I think you really have to think about what kind of business you want to build.
If you're going to run a facility, it'd best be very good, with some great gear, a nice tracking room, decent lounge, etc. And you're going to want to get a few other engineers involved. You really are trying to maximize the number of hours you can book, then raise your rate as you get busier.
Having a niche is a good thing. I've known lots of studio owners who kept their heads above water by doing repair work on gear for others, doing voice over stuff, phone on hold messages, etc.
If, on the other hand, you want to be a name engineer or producer, invest in a small mix rig with great monitors, and work as a freelancer. Find bands, and work with them. You may have to do the tracking for free (that is, the band pays whatever studio rent is), then charge the band for the mix. You have to build a rep, a good name with the bands in town, and with the studios.
If you want to have a facility to practice in, that can be another thing, but just do that. Find another band or two to split the rents with and just operate as a little practice space.
I'm just throwing ideas out there, of course, but I think you can see my point. Operating a restaurant isn't the same thing as being a chef, and being a studio owner isn't the same as being an engineer.