I've been loading these in 'windows' - 'user maps' & they are much better than the USGS Quads
http://svinetfc4.fs.fed.us/rastergateway/regions/regions.html The maps are in .tar.gz archives which are simple in linux, but 7zip is what worked for me in windows.
the 'nocollar' maps come in .tif's which won't load in TopoFusion so I opened the .tif in MSpaint & 'save to' changing to .png in the extension drop box (.bmp would work too, .jpg wouldn't).
Now you get to calibrate your map (I suggest you read the online manual here) this is going to be a little work, but you can keep trying until you are happy with the position. For me working with the 4m topo's was easiest. Pick a red grid corner close to a mountain or lake & select that point on both maps. you can do 3 separate points but 2 towards the corners works best (use the arrow keys to move you 4m topo to your point if it's off the page)
Later, mike
www.geekonabike.com