I have TopoUSA. It's not bad, but... Well, I guess it is bad. The interface makes little sense if you're a windows user, and the road database that they use is pretty bad. But the elevation data seems okay.

You might want to try http://www.bicycleclimbs.com. If you get to your area, you can find out the top and bottom elevations by clicking on a map. If you'd like, drop me a message and I'll set you up so you can default to your location.