garmin 500 would this unit be any good for a snowmobile? i called garmin to see if this unit dos a bread crumb trail they said no then i asked them some thing else they really don't know, so here i am asking if this a good unit to buy i need something with a big screen and that will put down a dread crumb trail so i can find my way back. trying to ride some new trails that i have never ran before and i don't know where they go. any help would be good. my friend has a delorme pn 40 it is really nice but the screen is to small for me.