Also, found this article where the directors from Cap: TWS talk a little about what we can expect in Captain America 3:
Thankfully the movie appears to be, in some form or another, a further continuation from where Cap left off at the end of TWS. Obviously Avengers: Age of Ultron will have taken place, but it appears that Cap will still be searching for Bucky in the third movie.
I'm also glad to hear that the movie will focus on Bucky dealing with his past as the Winter Soldier, apparently having him come into conflict with himself over his actions and if Steve will ever accept him after everything he's done.
There's also hint of Steve possibly passing the mantle of Captain America on to someone new, with Cap 3 being an "ending" of shorts for Steve's story. With how much focus the directors are putting on Bucky, I'm hoping this will lead to Bucky becoming Cap in the movieverse at some point, even becoming an Avenger.