I'm doing a no brothel run right now. It takes a bit of time but it's not hard to do. I have a decent sized motel, a fairly big bar, an arena but only for customers, nothing for slaves, and some living quarters for residents. Other than that, the girls I own are all gifts and such rather than from enslaving or purchasing them myself, I have the starts of a fairly large navy (About 80 drones, about 40 fighters, and about 20 bombers) and the girls not assigned as greeters or to my room are working in the lab doing research.
I think at this point, the biggest shortcoming of the game is no casino, . . . . seems that would fit the theme very well.