We tow our 2015 23IKSS with a 2008 Expedition EL, and it works well. Plenty of power and the extra long Expedition tracks well. I don't feel like the tail is wagging the dog. With all the gear in the camper, it weighs right around 6,100lbs. Our Expedition had the std towing package, but the RV dealer added the 7-pin wiring harness to allow for the electric brake, and we had our mechanic add the extra transmission cooler so we essentially have the HD towing package now.
Best advice I can offer is to be sure that you have your WDH hitch properly adjusted. This thread was very helpful for getting it dialed in:
Dealer WDH Setup Needed Serious Adjustments
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