Closing the loop in this a bit in case others go through this type of experiment.
Additional details needed:
1. These main steps assume you have all the SDKS already installed. I didn't so you need to download the combined SDK packages so you have all the needed EXEs to do the work.
2. The convim program mentioned above does NOT allow for converting to Extended BMP. That is actually a feature of the convimx program which is on the BETA page for download at the same site.
3. On Windows 10, getting the system to like msxml4.dll is a pain. I finally downloaded the latest SP3 version from Microsoft and copied it into every program folder the process uses and rebooted and that finally allowed it to serve up whatever COM interfaces are needed.
4. You must copy the biltmoreash.bgl file to your target scenarary as well. I didnt understand at first that is the placement of the model so it must be included as well. As best I can tell you dont have to convert it to FS2004 format. It just kind of works as is.
5. That being said, if anyone knows how to change the placement in the editor, I would love to try and move the biltmore a little closer to where it actually is. I dont think its quite that close to the airport in real life. If for example i know the exact lat and long, can i use a program to edit those into the location file?