Terri -
A time-based list would keep going out of date, so that wouldn't be helpful. What would be better is a series of articles, each one a review of a place you've been. That way people both learn about that specific location if they want to go sometime, and also get a sense in general about what a yoga retreat is like and what to expect.
You could do an overall "Planning for a Yoga Retreat" (if you don't have one already) to let a person who is going to one know what to expect and what to do. And then link to that to your reviews of the various specific locations you've gone.
