I really like the tutoring part of it, but I'm a teacher
I'd want to start a gym that had three different rooms. The first room would be the beginner room. It would have nothing but power cages, flat benches, barbells, and tons of weight. You would have to reach a certain strength level before moving on to the next room.
The intermediate room would have everything that the beginner room had plus a little more. The benches would be adjustable, there would be dumbbells, a few basic machines like leg press, hypers, reverse hypers, etc. You would have to reach a certain strength level to move on to the next room.
The last room would have an assortment of different bars, mono-lifts, bands, chains, machines, etc. There would also be a large assortment of strongman equipment.
Of course outside there would be hills, sleds, and prowlers.