What I would say for a West Marches style campaign is flesh out the setting using Microscope and/or Kingdom as well as watching Matt Colville's video on it.
I would be willing to contribute as a DM and as a player if this were Pathfinder. I understand that 5e has more support in general but 5e lacks customization compared to Pathfinder and when you're talking about dozens of players customization is going to be paramount, IMO.
As far as I know, this game is dead in the water. Feel free to try and run a similar idea as pathfinder. fair warning though: very tough to keep this going