One film w/ intermission might be best. It's hard to tell, having seen each of the first two exactly once now just how much is removable without making things confusing.

Also, a fun game to play is to watch the films and try to guess how things were different at some point of production. Things like the whole Bolg/Azog actor changes. Given that Bolg and Azog are both CG, and knowing what they did with Sauron-->Troll in ROTK, I suspect that Legolas's fight at the end of DoS was originally against the earlier version of Azog.