Sadly, I think the best boarding facilites are private and run a bit underground. When I lived in greater Boston, I boarded, unofficially and for a very low price, Yorkies that originated from my own breeding program. They and their owners were happy to have me as a resource at vacation time. Unfortunately, we now live in such a regulated environment that unless you have a secret, private, connection to a private boarding situation you'll have to do your own research on any commercial kennels you're considering.
Best wishes. I wouldn't dream of leaving my own Yorkies in the hands of total stangers. My travels require careful planning and having close relatives available daily to be in charge of carefully screened and vetted hired help. It's very expensive but still better than commercial kenneling, IMO.