Do you need 2 set of the basic game to play epic?  No, that is why they came out with the Epic expansion.  It gives you the 2nd board, more lore tokens, and a few other tokens to assist in using the game.  There is only one or two epic scenarios that require pieces from a 2nd game and both of those are the Reluctant Allies versions.

I too have been looking to expand my Battlelore base game, and I have another good question about the epic expansion.

Is there a way to randomize armies for each side, such as in Call To Arms?  Or does Call to Arms have something that takes Epic into account?  I like the idea of epic Battlelore, but it'd be a shame to only be stuck with the official scenarios. 

There are rule to set up Epic games with the call to arms cards. I am not 100% sure in which expansion they were, I think in call to arms.

The Call to Arms rules for Epic games (and Reluctant Allies as well) are found in the Epic expansion booklet, just after the Epic game rules and before the Reluctant Allies explanation.

Ok, thanks.  I have a general understanding of what's in Epic and CtA from what I've heard on the forums, but I haven't picked either of them up....yet.