Sorry I don't know what ORP or OPORD means. You might have a look at CompeGPS Land, it runs on Windows and MacOSX and has a free 30 day trial. It also interfaces with their Android and iOS apps. See this thread: http://www.laptopgpsworld.com/5528-compegps-land-mac-windows
You should not have to pay anything for the "classic" USGS topos, they are available for free from a number of sources however you need some technical knowledge to access and compile them.
The USGS makes their new topo product available for free on many platforms via the National Map. Personally, I don't care for these, but it what the USGS is currently maintaining and offering.
There is a free program called Mobile Atlas Creator that can download and process these and other maps in many different formats that can be used on Windows, iOS and Android. You could use its RMAP format to make maps for CompeGPS for example. But the CompeGPS program call also do this by itself. http://www.usgs.gov/newsroom/article.asp?ID=3580&from=news_side#.Vxobg-mcB5g
Personally I find Android and iOS devices better than Windows for this kind of thing. OruxMaps runs on Android and is free, it's my favorite. I also use Galileo on iOS and it is very good too, it costs $9.