the movie could/should be 120mins (2 Hours) with the first (Act) 40mins breaking down like this; Setting up the time frame its the 1940's that could be about 5 mins, 15 mins on Steve Rogers his girlfriend Gail and him getting into the Project Rebirth. The 20 mins on the 6 moths of training for Steve to become Captain America, as well as showing the rise of the Red Skull. The first 40mins would end with cap getting his costume and shield and heading off to war.
The Second (Act) 35mins would break down like this; 10 mins on Caps first mission and him meeting Bucky (he would be more like Brubakers bucky), and Bucky being assined Caps partners (Propaganda for the kids back home), 5 mins on Caps first meeting the Red Skull and Cap/Bucky trailing the Red Skulls and trying to stop his plans, and the last 20 mins would be caps mission to a Nazi stronghold on the coast of Iceland to stop a prototype hydrogen bomb from being launched. Cap falls into a state of suspended animation and Bucky is killed.
The Third (Act) 45mins would break down like this; the first 5 mins would be a deep sea exploration team finds the body of cap in a block of ice. 20 mins on cap being brought up to speed on all the time that he has been gone, being reintoduced to the world and showing the Red Skull now possing as George Maxon, an American businessman and leader of AIM and his plans. and the last 20 mins Cap is called on to stop the Red Skull with a battle on the top of mount rushmore to stop the Red Skulls new plague.