http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/07linmg1e.pdfLook at page 16. Looks like 30,000 miles to me.
Change automatic transmission fluid on vehicles
equipped with the Torqshift transmission. Replace
the remote filter element on the vehicles
equipped with the Torqshift transmission. Inspect
automatic transmission/transaxle fluid level
on all other vehicles, if equipped with dipstick.
Consult your dealer for your particular
requirements.
And didn't take the time to see if "towing" put you in "severe" maintenance schedule.
(edit part) look near end in the "SPECIAL OPERATING CONDITIONS" that is schedule I would keep.