When you get tired of trying to deal with the new Bertram corp, Call High Tide Marine in Marathon FL,(keys). They speak old Berts and usually have the specs on the older wagons (Pre-FEBs).
I believe Bertram uses Joule Yacht. I know they did at one time. There are many yacht transport companies. Yes they require two escorts, sometimes a pole escort as well. In some states and areas maybe even police or patrol escorts. But they can be moved by truck. The biggest issues relate to preparation and reassembly and to total cost. Is it likely to be justified on an older boat with seized engines? No. But it can be done and quotes can be easily obtained. It also takes a good bit of preparation and time as permits have to be obtained for each state and states do not rush those permits. There are lots of very large boats on inland lakes. Look at the 80' and up houseboats on Lake Lanier, GA. Look at lakes like Lake Texoma that have yachts on them for reasons unknown to me. Even Lake Norman, NC has some outrageously large boats for a relatively small body of water.
Ask a shipper first. I shipped 63' of boat 17' wide from LA to Miami, as long as the bride can be broken down and the load height meets the targets, there are many routes off the beaten paths that can accomplish this task. They usually arrived with pecans on the bridge courtesy of some off-highway routing in Georgia. No fuel/water or waste. Sometimes (not usually) takes a second truck o bring bridge/tower. How do you think the 54 Bertrams sold over the years (back to the 80's) arrived in SoCal? How do you think the larger Marquis make it out west??