GPS, which unit best for Off Road

[AndyB]

Ready to buy a GPS and have tried reading and weeding through the many threads here. Yet still wondering which unit? ( it seems that the Garmin family is what most use V,176,276) will best fit my needs, which is almost totally off road….. Going to use it on both the 640adv. and 400rxc ( especially the 400! Since I find myself using this bike to really get lost on. soooooo tired of running out of gas or riding down into some hillbilly's back yard and being chewed on by mean dogs before i can get turned around)….. Looking to make use of the USGS and Delorme map software. Any other programs out there that show fire roads and landmarks (power lines, gas lines, water tanks, etc…..)?........ As far as mounting them, looking to hardwire unit to both bikes. Where to do this? And any quick connect/disconnect plug work? Or is there one ready made?..... Also are these units waterproof? Or is there a way to waterproof them? Been caught out in some real nasty down pours and would hate to see all those $$$$ fizzzel out!......well, any help (point me to the proper thread) will be so appreciated, thanks…….AndyB