We are having a very similar experience. Tires are about a year old, but the vehicle did sit the last 5 months. The strange thing is the intermittent part of it. Did not have this happen before, now we are on a trip, and notice a severe vibration from the front end, coming up through the steering, starting at about 45 mph. Did not start until about 10 mile from the house. stopped and it cleared, but started back up again several times over the next 100 miles. Visual inspection during rocking the steering show maybe a very little play in the upper right rod joint. removed wheel covers and inspected tires, and found nothing.
Did research on line, and it does seem to be an issue with ford front ends, but suggestions are anything from a sticking park brake, brake caliper, wheel bearings, or tire separation. I am thinking it would not be tire, front end, or wheel bearings, and leaning toward a brake issue because of the intermittent nature of the problem?