There are many kinds of software that are useful in various aspects of benchmark hunting. This is a place to discuss what each one is for and provide detailed instructions on how to use it.
There are two sources of files of benchmarks. The softwares described below can then be used to convert these benchmark files to the .gpx format, a format that several GPS-oriented softwares can read and process.
The Geocaching site's Benchmark Hunting page has a place to put a Postal (Zip) code and a sub-page, accessed by clicking on "Other search options" has a search by coordinates feature. Both of these search modes will bring up a listing of benchmarks on your screen. In the listing, selecting and clicking in the boxes on the rightmost ("d/l") column and then clicking on the "Download Waypoint File" at the bottom of the screen will provide a .loc file to your computer. The .loc file can be read by both the EasyGPS software and by Google Earth. EasyGPS can be used to convert the .loc file to a .gpx file.
The NGS Datasheet Page provides a beginning point for several choices of benchmark file access systems, all of which result in a listing of NGS datasheets in a .dat file. The BMGPX software can then be used to convert a .dat file to a .gpx file.