I would never buy a boat without doing a sea trial, and personally inspecting a boat--even if someone had scouted it our ahead of time. I have bought boats sight unseen--until the time when I paid off the boat, and took delivary.
If you need shipping there are boat haulers, and "U Ship" where you get bids to move a boat. I have used this service once with a boat larger than a C Dory--and it worked well. The boat was brought from Lake Michigan to Pensacola--about 1200 miles; in my case it was a dollar a mile. However, today it will be $3 or $4 a mile.