Hi,
You can look up the towing guide, and see what vehicles can be towed 4 wheels down without a tow dolly. The 2014 MKS, MKX and MKT are listed, can not be put on a tow dolly with all wheel drive, but can be towed 4 wheels down with either AWD or FWD.
http://www.fleet.ford.com/towing-guides/ I think that if you have ever used a tow dolly and then went to 4 wheel down again, you will agree that 4 wheel down is the way to go. I had a Honda CRV with 4 wheel down towing, then started full timing with my Windstar van and tow dolly.
Now I have a Edge, and love it much better, no need to find a place to put the dolly at camp, then back in the motorhome, then park the car, all while holding up traffic. Now I just stop, unhitch the car in a few seconds, unplug the wires, and then park it in a empty site, back the RV into it's space, and I move the car in front of me.
The 2007 Edge can be towed 4 wheels down in either AWD or FWD. I have AWD, so can not use a tow dolly.
I installed a diode kit in all of my towed vehicles. Yes even the van, so that the red tail light would turn on with my motorhome taillights. Then ran wire from the diodes to under the hood, and then to a connection to the motorhome.
The V10 makes about 100 more HP than my 97 Bounder with a 460" V8 in it. You will have no problems going up the hills. You will also have either a 5 or 6 speed transmission, so can make it up the hills even easier. Due to the reduced weight, you probably can take hills faster than your DP could.
The V10 has tiny pistons, moving a short distance with just 0.68 liters per cylinder. It can run 4,000 RPM for hours on end without a problem. Your DP might have had a 9 liter inline 6, with 1.5 liters per cylinder (think 2 liter soda bottle but slightly shorter). Turning that engine at over 2,700 RPM would be impossible due to the governor. It is the higher RPM's that give the V10 it's horsepower advantage. Run it at 4,000 and it will produce a lot of power. But get worse mileage. I would rather take it easy up the mountain pass, and save the fuel. I keep my motorhome around 45 MPH climbing to save fuel. You might find that your V10 works well at either 50 or 45, depending on the gear and engine RPM.
Fred.