More than a couple of days stay....
”
Behnken and Hurley have been completing training for the mission, such as a series of simulations from launch to docking as well as undocking and preparations for re-entry and splashdown. They have also been training for ISS operations, given that their mission, which originally was to spend only a couple weeks at the ISS, will now likely last for two to three months.”......
NASA has already named the crew for the first operational Crew Dragon missionto follow the Demo-2 launch. That flight would launch NASA astronauts Michael Hopkins, Victor Glover, Jr., Shannon Walker and Japanese Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi to the space station sometime after Demo-2.