I'd do it in some nice van. Probably the newer version of the Nissan Interstar / Renault something..
Odd choice yes, why ? Because it is surprisingly light, you can carry everything you need, it's heavy and stable on the motorway and the suspension is good. Also being able to look out over the other cars (including even the largest SUV's ) is really handy and makes so that you feel less fastly tired because you can look ahead much more. Torquey diesel engine makes for no shifting AT ALL even on the hilliest motorways.