>The Microsft TerraServer topo maps appear to be the 100k series, not the 24k series.
You may have to zoom in more. I've compared both the USGS Seamless and TerraServer maps with my NG Topo! quads and they are exactly the same at the 1:24,000/7.5' scale. This URL will drop you into a 7.5' map of where I spent a blizzardy night in my hammock earlier this year while ski-packing.
On USGS Seamless, after you have zoomed in to 1:2,810,005 or closer, check the Orthoimagery:DRG Mosaicked Image box. It will switch to 1:24,000 when you zoom to the 1:21,953 scale. (I have no idea if those scales are used everywhere or if they depend on previous viewing, but they should be close.)