They are right. The 61 stuff you could run out of a hangar if you really wanted to. The 141 stuff is much more complicated. There is a lot of red tape with the FAA and it takes about 2-4 years to get a location certified. The 141 school I worked for previously had several locations in the same state. Each location had to be in operation for at least 2 years (I think it was 2, could have been more) in order to get 141 approval. They do not just approve 141 for a company and allow each company location to operate as 141, it is site specific.
First place I would check, insurance. I think you may be surprised about how costly it is going to be to cover your operation. Insurance and maintenance costs will kill a flight school quicker than anything else.