There are many vehicles that, as cars or trucks, can not be towed 4-down.
however conversion of an auto-mobile into a true trailer is fairly easy on many models, a company called Remco Towing sells the conversion kits.
Front wheel drive: "Break" a half axle, That is put some kind of locking clutch on the half axle so that the wheel turns freely and the other will turn the differential but not the transmission, you tow in park.
Rear wheel drive "Break" teh drive shaft with a spline clutch, Again rear wheels turn easily, transmission remains in park.
And there are other options as well.
Home is where I park it!