Following suggestions from this forum and SiennaClub
, I mounted my Prodigy using the metal U-bracket and a custom aluminum base onto the retractable cupholder/coin tray in the middle of my dash. When not towing, the controller is unplugged and stored in the console bin between the seats, the end of the wiring stows in another bin, and the cupholder can retract.
Other Sienna owners routinely mount their controllers inside a tilt-out bin at the bottom of the centre dash area (the same one my wiring comes from and stows in) - that's too far down for me, I and don't see how they keep it from moving (the controller needs a stable mounting point), but they like it.
I have no idea if a Highlander has a similar cupholder or bin, but the idea is to think of new uses for some of those clever interior fittings.
Having just bought a Highlander Hybrid for both the mileage and environmental benefits, I now plan to tug my Surfside behind it ... negating most gas benefits I would normally get (at least when I pull the trailer). Makes sense eh?
Actually, yes, this makes perfect sense to me. The hybrid drive system will be beneficial for most driving - which is without the trailer - and will at least do no harm while towing. Since Toyota's Synergy drive system acts as a continuously variable transmission I expect that it will have some benefit for towing, allowing engine speed to rise as needed without dropping down a large gearing step.