Towing with a Ford E250 Van (4.6 liter, V8) in the mountains

My 2009 Ford E250 has a maximum tow weight of 6100 pounds. I will be towing a Jayco X17Z travel trailer with a Gross Vehicle Weight of 3,500 pounds. The spec’s on my van are 4.6 liters /v-8/ 225 HP/...