Re: Steam: I'm not sure if/when that'll happen. Making it available for DRM-free versions of the game would require developing and maintaining a separate version of the mod (any call to Steam functions with Steam unavailable hard crashes the game). If this was being made officially, it would be developed with that in mind, but as it stands, this is an unofficial mod that I develop in my free time, so I had to make sacrifices to be able to do this at all.
Re: Mods: Currently all mods are uploaded and hosted by their authors so you'd have to ask them. It is said that a section for NTT mods will appear on ThroneButt in future, which should lead to most mods being hosted there instead of dropbox/mediafire/pastebin/...