Here are several photos of the USNS SPEARHEAD (T-EPF-1) which show the capabilities of the EPF vessels. This photo nicely the catamaran hull.
The helo deck can take even the largest Navy helicopter.
This shows the ramp operation for driving vehicles on and off the ship. These vessels at NOT warships, hence their civilian merchant marine crew and the fact that can only operate out of secured ports.
This cut away view shows the mission bay as the lowest level of the ship. Above that is the passenger area which can hold 312 passengers in airline type seating with a galley and mess decks plus sleeping accommodations for about 150 people. The top deck has the helo deck aft and the bridge forward with the crew quarters aft of the bridge.