Unfortunately, there is no large active forum covering B-17 The Mighty Eighth like there was when bombs-away.net was active. This GOG forum and the one on Steam for this game are the most active today.
Not sure if you're aware but I've been publishing a long Getting Started video series on YouTube for the game :
https://www.youtube.com/playlist?list=PLV6qAKzfD-icnl7cMeIR_ldvH6twjQdtI. The series isn't complete so if you have any how-to's that you can share then I'd love to see them.
I have also been compiling as many of the original downloads (mods, skins, R&R files etc.) that I can from lots of different sources (including a few of the bombs-away members that have contacted me), organising them and packaging them up for release when I do a video covering modding the game. So, if you're willing to share, then I'd love to be able to trawl through the files you have to see which ones I don't have yet.
Cheers