I’ve seen a few Airstream’s being towed over the last year or so, usually the smaller ones, there used to be one fairly local to me, but it may be tucked away for the winter.
Spot on mine would have to craned over the house into the garden so i reckon a shepherds hut can be built in situ.
A ‘proper’ Shepherd’s hut will have basically a steel/iron bar as an axle bolted to two heavy wood cross beams, one on a swivel, with iron wheels fitted. They were only ever designed to be moved occasionally from one field to another by horse or tractor, so they’re normally trailered to wherever they’re going to finish up.
A close friend has two in her garden, both original that have been restored, one is mid-1800’s, IIRC, the date is carved in one of the axle beams. One is used by staff if her hotel gets really busy and their room is needed, the other is for customers to book for B&B, and is very popular.