I spent quite a bit of time on this issue myself. I wanted GPS functioning "in-panel" in the 2d and vc, as well as a drop down; and you're right the multiple panel files in the Aeroworx King Air can be a bit intimidating.
I started out installing the default GPS in place of the WXR. After many differerent versions I finally found the Friendly Panels - GPS Pack. (Its available here in the fs pilot shop at a very reasonable price. I use it on just about all of my aircraft now)
I now have the GNS 430 mounted in panel and functioning in place of the KLN90b and the GNS 530 in place of the WXR. I like the combination very much and as far as I can tell the functions in both the EFIS and analogue cockpits all work fine. I mostly fly in the analogue cockpit.
I would be happy to share the files with you or anyone else interested, although I have never shared files before and don't really know quite how to go about that. I don't think there are any copyright or other legal problems but I'm really not sure.
Alternatively I would also be happy to offer any guidance through the process if you would like.
Good Luck with however you decide to proceed!!
"...eyes ever turned skyward."
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