The position, direction and up should be sufficient to capture the camera view. This is my go to snippet for saving camera views: How to share custom Sandcastle examples.
// Set the initial camera view to look at Manhattan
var initialPosition = Cesium.Cartesian3.fromDegrees(
-74.01881302800248,
40.69114333714821,
753
);
var initialOrientation = new Cesium.HeadingPitchRoll.fromDegrees(
21.27879878293835,
-21.34390550872461,
0.0716951918898415
);
viewer.scene.camera.setView({
destination: initialPosition,
orientation: initialOrientation,
endTransform: Cesium.Matrix4.IDENTITY,
});