I completely understand your fear of not getting there in time, as I had the same fear. You do not have to worry about missing ovulation because you will be monitored by a local fertility doc, who will let you know when your eggs are nearing maturity. Also, I was given a trigger shot which causes you to ovulate within 24 to 36 hours. My husband gave it to me in the airport terminal while we were waiting for our plane to arrive. Everything is timed as accurately as possible so the iui can be performed at the right time.
I do want to add that with my first cycle, i did clomid and did not get a trigger shot. I got pregnant but miscarried. The second Iui, I did injectibles and was given a trigger shot. I believe the trigger shot really helped with the timing of ovulation.
As far as cost goes, each trip including travel, hotel and food cost about $5 to $6000. The second iui was the more expensive trip because I was on injectible meds which cost over $1000.
I know everything seems confusing and scary, but once you start the process, it is easier than you think. Good luck with everything and feel free to ask any questions you have, and please keep me posted on your cycle plans.