Steve no need to do that you can check in advance if one of the drivers has a passenger seat open then join him and share the cost of petrol. I did it last year and made many friends along the way.
I had plans to go this year too, however, had to cancel due to family issues.
Dieter
PS. Mind you shipping the car to Europe and enjoying it there like 3 times 2 to 3 weeks each time is in the back of my mind. I need to investigate that.