So, it appears that unlike the 66X units, we 350 users cannot import an externally created track (like an offroader might make in BaseCamp for navigating in areas with no mapped roads) and then view it on screen. This would be a really handy feature, and since they already have the code for it for the 66X units, I cannot imagine that it would be difficult/costly to add it to the 350. I can understand the 350 not having non-navigational features like playing MP3, but in my view there is no excuse for removing navigational features from their top motorcycle GPS.
I humbly suggest that anyone reading this go here (if you have a 350): https://support.garmin.com/support/searchSupport/escalateForm.htm
or here (if you do not have a 350): http://www8.garmin.com/contactUs/ideas/#container-form
And respectfully request that they add this feature to the 350. Perhaps if enough people ask for it, they will do it. At any rate, it does not hurt to try.
Thanks for reading!