Yamaha 1300 Tourer - Yamaha 1300 Tourer Fansite

I'm in the early stages of planning my first tour and realize that a GPS is going to be my best friend on this trip. I've been using one for a few years but never on a bike. There are three items that I'm trying to figure out:
1. How to get power to my GPS (that I haven't purchased yet)
2. How to see my GPS during the day
3. How can I hear my GPSs directions, and music, in my helmet (I wear a modular helmet)

All suggestions welcome!

Thanks,
Peter