I am a big fan of using National Geographic's Topo program for looking at topographic maps. As they are seamless sewed up, they allow for a seamless viewing of an area.

You can find the product here at:

http://www.topo.com

I have been using the Notes and Photos portion of Topo to link to an external document. That eternal document is a kml or kmz sitting on a server. Importantly, it allows for a satellite/aerial view of the same coverage.

Any further ideas on using the two concurrently?

My first idea is going to be implemented in a Geology 100 course at a University for teaching landforms.