I think the hardest part of filefront going down is the loss of the system for "browsing" the mods before you download. Nothing like a series of screenshots and a review blip to give you a sense of what you are in for.
That said... When you want to "browse" Filefront for mods, just use the Way Back Machine.
https://archive.org/web/)
I find it's sufficient for looking around and noting the exact mod name I want, the mod author, as well as the zip name, and all the screenshots, reviews, and blurbs I'm used to seeing on Filefront. Only negative is its a tad slow. All that information can be used to dig up another location. If it exists.