Sorry that I'm been busy all the time so I just saw your message.
I'm now mostly keen on the locomotives and the season pack will be delayed cuz I saw your work and find it very nice,hahaha...
I can help you with the ATLAS_billboards,just give me an E-mail and I'll send it to you.
Yes it is the TF sunrise skybox and that's why I never release it cuz I cant connect with the author.
Actually I made a liitle change to .HDR with the skybox to make it look nicer.
I have your mod and a really nice one,haha