I am very slow to provide any type of information without being able to confirm that the client is using the information properly.
In a case like this, I would attempt to find a train living closer to the client to refer to them.
If that is not an option, I would try to utilize some type of video link. Like Skype, but even that makes me uncomfortable. How can I help them if they have a medical emergency? Or if they get injured accidentally?
So far, for me personally, the referral has always worked.