As Jim mentioned, the only option to tow and keep the lift is to use a tow dolly (drop axle) like the Automated Safety Hitch System. Currently it's the only system on the market. Otherwise, you'll need to remove the lift from you truck.
I looked at the website for this and was starting to get all excited. Maybe I could someday graduate to a 5er! (We have to have a eight-seat vehicle for kids). They even had a picture of an Excursion towing one!
But then I started thinking and reading about it more - could I even pull a fifth wheel? My 2003 Excursion has a max towing of 12,000 lbs. The tow dolly probably weighs 1000-1500 lbs. So in reality that would leave me with just over 10,000 lbs of fifth wheel and no cushion. Aren't most of the Heartland fifth wheels 14,000 lbs and up? Or am I calculating wrong here?
Guess I'm stuck in travel trailer realm for a while.