I have been adding data to OpenStreetmaps
(OSM) from both my GPS tracks and also "CanVec" data. There are still hundreds of backroads throughout BC that aren't on any freely available maps like OSM. Since Geocachers like to explore and have their GPS's with them it seems a natural fit for them to add/contribute to OSM. If there is enough interest I will host an event in the New year/Spring that covers the basics of adding roads and data to OSM from GPS tracks, Bing aerial images and CanVec data.
For those looking for pre-made Garmin maps from OSm data you can find them here:
(not my maps BTW, I just use them on my (Oregon)