Any good salesperson will tell you that one of the best ways to close a sale is to make a limited time offer. The same applies in the employment field.
If you are having difficulty getting interviews set up, tentatively schedule a visit to the area, possibly over winter or spring break, or even during an extended weekend. Then make a new round of phone calls. This time, make sure you note that: "I plan to be in the _____ area Monday through Friday, March _____ to _____" (or whatever your time frame is). You can also utilize the Alternative Choice Technique by stating: "I have Tuesday, Thursday, and Friday open. Which of those days would be best for you?"
If they balk at the opportunity to meet with you, remind them that you will only be in the area a short time. "After that time, there would, of course, be travel expenses involved in getting together." If they have any inkling of interest, they will get the point. This is a limited time offer. If they have any interest in interviewing you, they had better do it when you are in town, or it will end up costing them $500-$1,000 for the plane/hotel/rental car routine.
This technique also works well once you have one interview set up. If you are being flown in, ask for an extra day or so to scout the area, or ask to stay over the weekend. This will give you the chance to meet with any other prospective employers while you are in town. If you are staying extra on Company #1's expense account, make sure you do actually spend time looking around the area and not just meeting with Company #2 and Company #3. If that is the only reason your hotel bill is three nights instead of one, you have an ethical obligation to pick up the extra two nights' expense.