I got the USA maps working.
In order to do this, uninstall Navigon.
Get
Map loader for navigon select. Read all posts as I had to change IP in my hosts file to my PC's local IP for the app to connect (Zune must be running & PC Internet Enabled, Disable WiFi & Cell Data on device.).
Follow steps listed in the app except what I noted above. Install Navigon, Select Maps, Click Proceed. Right Windows will say Web Server Running.
Open Navigon on device & perform download as app requests. It'll download files from the Map loader Web Server.
Close Navigon.
At this point all files & maps are loaded but some need replacement for the maps to work.
Download ZIP & Extract. Now using
WPDM's File manager, copy "filelist.xml" & "NaviKernelConf.ini" to "\Applications\Data\6F9CB464-BDAF-DF11-8A2F-00237DE2DB9E\Data\IsolatedStore\" overwriting the existing files.
Browse on PC to data folder for map loader (Example: "D:\Downloads\Keith's\HD7 Stuff\Map Installer\Data\o25\u\eu\wm_select\Data\"). Copy my files in zips Data folder to Map Loader's Data folder replacing existing.
Start Task Manager & close "wsNavigonGui.exe" under processes tab (I've noticed it may stay load & prevent the Web Server from loading in next step, If it is not running skip this step.).
Open Map Loader again, select one map & click proceed again (Make sure WiFi & Data are still off on device).
Open Navigon & it'll prompt to download again, let it do so, it should now download the files from my zip's data folder you just copied over.
Now USA maps should work.