I may be a bit slow, but I finally figured out that just because the 600 does not have a camera it doesn't mean that you can't put geotagged photos on it or in BaseCamp.
I have a Panasonic Lumix with GPS that I never enabled because of battery life, so I just tried it. Took some pics with the GPS enabled, popped the camera card into the computer with BaseCamp running, BC recognizes card and the pic, copied the pic to a list, it shows up correctly on the BC map, sent it to the Montana.
Enable the photo viewer icon in a profile, the pics are there, click one, see it, use options menu to show on map, and Lo and Behold, my photo is right there on the topo map where I took it!
Another way to use up a lot of disk space in the computer and the GPSr....
Interesting to note that even if the photo has already been loaded into the computer via a photo editor/organizer, BC makes a copy of it in it's own folder, and even if the photo has GPS info in the EXIF, it has to make a little file to tell itself where to place the photo on the map.
Presumably the Montana does not, and is just reading the EXIF tag.
AND, you can drag any photo on your system, geotagged or not, onto the BC map from your photo editor/organizer, and place it where the pic was taken....(if you can remember.....)
Presumably lots of you already know this, but I'm old and slow, so it took me 10 months.