Don't want to sound like an asshole, but considering the actions of a couple right-wing governors, we do have an group of potential talent in the city. Scope out around the times square and port authority areas, near the hotels.
They will probably be lower end, more of the $100-200 instead of $300+, but it beats selling candy bars and chocolates that they're making these kids do on the subway. I think the ladies will like the easy money.
In terms of the business, you are renting space to these girls. Are they banging customers on the living room table, in front of you? If not, you don't know what is going on in the room. You're operating the "Holiday Inn and Out." The negative aspects are removing the soiled sheets and pillowcases after each encounter, and mopping off the splooge from the walls and floors everyday.
The barriers to entry I think are quite low. If you wanted to do it yourself, is a member of the "local crime syndicate" gonna knock on your door and ask for a cut like they're the mafia? Is this a movie?