There are some major differences between the software that can be used on FSX versus what is required for P3Dv4x: Some of the older models can't be use in P3Dv4x and gauges airplane sound configs and effects are different in P3Dv4x.
There is a few things you have to do with Tongass to make it work in P3Dv4x (Terrain.cfg)
alike the AS Beaver project to make it work in P3Dv4. and a couple of the ai models in RTMM have to be updated for use P3Dv4x.
Refer to the P3Dv4x section here: Step tables 5-8, 9.
https://return.mistymoorings.com/getting_started/index.php#5https://return.mistymoorings.com/getting_started/index.php#8https://return.mistymoorings.com/getting_started/index.php#9AS Beaver conversion to P3D: LINK:
https://return.mistymoorings.com/faq/Now also be careful with the new Orbx Central (v4) (current v 4.0.39). Once you have RTMM LIbs in and Tongass in, the insertion points in Orbx Central must be correctly set or your scenery layering blocks will be incorrect.
Set insertion points:
Orbx Airports and regions entries must be placed below RTMM LIBS, and
Orbx Global openLC must be inserted below Tongass Lower.
Can give you hand Carl later on some of this stuff after you have the sim installed on the new puter.
Norm