StarGirl:
I've seen a few threads on this forum about regional interviews. These are interviews, usually conducted in your region of the US, by representatives or affiliates of the school which reside in or near your area. You might consider contacting the schools which have granted you interviews and asking them if regional interviews are possible. The obvious downside to this is that you don't get to visit the university and get first-hand impressions about the atmosphere, facilities, etc.
Otherwise, try to schedule your interviews such that you can visit several schools in close proximity within a given week. Maybe plane tickets or rail fares between these proximate cities will be cheaper.
Good luck!
Smile_doc