I have 15,000 plus miles towing a Smart car, four wheels down, behind my restored 1973 GMC.....max elevation so far was over the Continental Divide at Cottonwood pass.
The most important thing is to get a good tow set up for the Smart. I tried to tow it with the towing rings in front and pulled them out of the car. I use a Blue Ox set up on both ends and had the rear lights wired to a plug on the front.
On side trips, we have put another 12,000 on the Smart and find it great on dirt roads up the mountains.
