I'm glad to hear that you are enjoying the maps! I don't have a tutorial for pulling data off of the GPS, but I do have some pointers regarding data recording here: http://www.switchbacks.com/nwtrails/default.aspx#contribute
. The main thing to keep in mind is to not do a "save" on the GPS (that reduces the number of points in the data), but rather just copy the tracks directly from GPS to your computer. This can be done by connecting the unit to the PC and either downloading via MapSource or using Windows Explorer to copy the .gpx files from GPS to hard drive.
Yes, NW Topos contains all of the trails that NW Trails contains, at least within its current area of coverage. NW Trails is transparent, meaning that it will overlay other mapsets you have loaded and allow you to see the trails on top of the other maps, whether they are street maps, topo maps, et al. It's handy to have both mapsets installed so that you can see the trails when driving around town and the like. NW Topos is more of an all-in-one mapset that includes roads, contours lines, hydrology, trails, etc. It is not transparent, so you can't overlay it on top of other maps.