Have you considered buying a TriLift? This is an electrically operated power lift that attaches to your tow bar. It is a bit like a bike rack for your Segway PT, but electrically raises it and locks it into place.
The TriLift is mostly used for mobility scooters, but they make (or have made) an adaptor for the Segway PT. Or someone could make one for you quite easily.
The following video clip is slow and loud but it shows how it works: