If a fraternity is asking to do a mixer with you, they should be aware already that you don't have a house. If they don't want to host it at their house, they should be prepared to rent a space off-campus before they even ask.
Since we're in the middle of a big city, we have no shortage of places we can use for events. We have bid night dinner and sweetheart dinner in a particular local restaurant. For most other events, we rent spaces in the area. I can see how there could be much less to choose from in a smaller town, but area businesses should be willing to work with you. Good luck!
