The 310XT will not give you turn by turn directions, but you can use the map feature to display the 'breadcrumbs' of courses. I use this frequently, and especially in places I am not 100% familiar with. The one thing that always confused me is I would call what I want to do a 'route' and Garmin calls it a 'Course' A 310XT will not display a 'route' on the map, but it will display a 'course'. The one issue you have to watch out for, is when the road you are on makes a gradual turn one way (right in my case last weekend) and the road you are supposed to turn onto makes a gradual turn the other way (left for me last weekend). The breadcrumb will display it like you are going straight since you can't see the other roads and then you end up following the road right and going off course.
DCRainmaker has a good article on how to map using Mapmyride and then transfer it to your 310 using Garmin Training center
http://www.dcrainmaker.com/...ourses-for-your.html. I have also used Garmin Connect website to create the maps, or to import routes and convert them to Courses. The Garmin Connect seems to be particular about the format of the .GPX file you send it, so I have been converting the GPX files from Mapmyride or other GPX files to GPX tracks using
http://www.GPSIES.com (but it the site seems to be down right now) and then importing to Connect and converting to courses and sending to the unit.
You then go under 'Training' in the 310 menus and select courses and whatever you named your course.
I am working on a description of how to do this for our club webpage, so I'll PM you the draft to see if it makes any sense.
Tim Anderson
"It's the nature of the internets that you get some dweeb who knows nothing about (insert topic here) pontificates about (topic), believing that his/her opinion is worth the same as opinions from those who actually knows what's going on." --Echappist