It's good that they give the specs ahead of time, but it's even better that they let you download the instruction manuals as well.
Here's a link to the manuals for the Nuvi 760. (I attached 'em below as well)
There is the same manual for the 750/760.
Check the manual for everything that you might want to do with it. If it's not in the manual, the unit can't do it; it's really as simple as that. The 760 looks like it does allow you to load routes into it. I'm not sure whether it lets you load tracks, from the manual it appears to not be able to do that. Also, it doesn't appear to manage a trip log / track log at all, so you may not be able to save your track and upload it to your computer later. For $250, it's definitely a good deal, but I do think that it is missing some things that I'd want in a motorcycle GPS.