We have flat towed vehicles for a number of years. Starting with a Saturn SL2 behind a 330hp Fleetwood Discovery to a Ford Flex behind the Discovery and now the Flex behind a 2012 Berkshire 390bh-60.
The Saturn was a dream to tow ... I could hardly notice the extra weight. We loved the car but found that my son was getting too long in the leg to be comfortable in the back seat.
Outgrowing the Saturn forced us into looking for a new vehicle to flat tow. One that would accomodate two adults, two growing kids and two dogs. We settled on a 2010 Ford Flex Limited AWD. (I believe this is built on same platform as the Ford Edge). It has been a wonderful car but is much heavier to tow. Although towing on the flats was not a problem, we did find that the long steep hills between Alberta and San Diego were a bit of a challange with the 330hp Cummins.
When we upgraded our coach in September of this year we made sure to go with the larger engine to give us the 360 HP and more importantly 800ft lbsof torque.
We use the new Blue Ox Alladin tow bar that is rated at 7500 lbs. This is a wonderful system. Exstemely easy to use, small and easy to store ... and no unsightly hardware on the car.
We also use an BreakBuddy. A system of this type is required by law in many states and provinces.
To tow your vehicle simply do the following;
Hook up tow bar
Connect power cord to MH and Car
Connect safety cable ... make sure to cross sides
Connect breakaway cable on break buddy
Install BreakBuddy adn follow setup procedure
Put vehicle in neutral and turn key to acc
Check all lights and signals on MH and Vehicle
Go on your way
Ford recommends not towing over 65 mph
At the end of the days travel I will either run the vehicle for a while or put on a battery minder as BreakBuddy will tend to run down battery over time