Today I tried to download some waypoints I created in Trails.com in GPX format and import them into Garmin's MapSource. It didn't work.
Is there a way to import waypoints or routes in GPX format into the Garmin unit?
File => Open => GPX didn't work for you?
Or am I stuck buying topos of the each state I want from Garmin?
For off the shelf mapping you're pretty much limited to Garmin's MapSource products. You can find info and a map viewer at the following link. http://www8.garmin.com/cartography/
There are 3rd party topo maps available for Wyoming and Colorado.