My long rides on the Speedy are helped by two things.
I use the beads for my seat, makes a world of difference. Got mine from beadrider.com but you can also pick them up at Walmart for cars. Just cut it down to size.
The other easy fix is to hook your heels back on the passenger pegs (sort of the jocky position). Takes all the pressure of the backside for awhile. I also have the floorboards so I tend to vary my position alot and the miles just keep racking up.
Give me a shout when back in town, always looking for a riding partner.