The 4th age?

Has anyone ever come across any meaty material suggesting what may have happened in the 4th age?

I have read that Elessar strove to reunite Arnor and Gondor, but little else on a similar scale.

What of the Elves? So they all sailed away to The West but what of the Moriquendi? Would they have stayed?

What of the Blue Wizards, the two Istari that were 'unaccounted' for? It is said they passed away to the East, could I hazard that they influenced the Easterlings? But in what way and would they then have been in league with Sauron?

So much that would have happened afterwards still vexes me. I would love to hear any of your theories~!