Awesome!

Now pardon me for stating my interest and..eh crapping on the idea in such a short span of time, but why does it have to be set during the War of the Ring? Is it relevant to the plot or something? I feel like this particular time-period has been done to death and it's also quite restricting. It's basically the endgame - the lines have been drawn, we know the sides, we know their motivations, we know who the heroes & villains are....ultimately everything is centered around what happens in Gondor and Mordor. We don't have a lot of information about the East, but presumably it's firmly under Sauron's dominion at this time, isn't that kinda, I dunno, boring? Outsiders like our characters will be noticed immediately and will there even be any meaningful interaction apart from fighting? What's more, what motivation will our characters have on going on this journey, when Sauron's forces are actively trying to destroy their homelands? 

Don't get me wrong, I like the premise of the plot, I just think that the period should be tweaked a bit. A better fit in my opinion would be during the Watchful Peace (2063 TA - 2460 TA) or some time after it. Why? Well for one, Tolkien hasn't written much about it, so we have more room for creative freedom. Additionally, the Easterlings haven't all united under Sauron, so there will be more variety (as opposed to "all these evil men worshipping the Dark Lord"); in fact, if I remember it right, Sauron himself was active in the East during this time, so that can be a theme as well. 

Just my 2 cents.