Found this website online. Great place to download some free topos of your ao.

http://www.digital-topo-maps.com/

Thanks for the link, good way to get topos.

Here is a link to older sectional topo maps. http://libremap.org/data/
Many show old roads & rail that are no longer listed on the newer maps. More of a pain to navigate than your link. Several hiking trails in the Ozarks were at one time a road, of sorts.

Here's another. You can buy printed ones, or download them free.

Http://www.usgs.gov/

Here's an article on an open source map project. It looks like a viable source of maps to me. My urban AO is already finished and seems to be accurate. Although I would refine the detail of landmarks if could.
http://www.networkworld.com/communi...-side?source=NWWNLE_nlt_linux_2010-07-14

http://wiki.openstreetmap.org/wiki/WikiProject_United_States

And the 3per's blog was just discussing this.
http://sipseystreetirregulars.blogspot.com/2010/07/praxis-maps.html