Well, it's fun if you have to sneak in somewhere, but three times? For the same portals? No, it's a bit exaggerating. There are some new portals left out from the banner, the route should be re-thinked.
Great picture of Marvin, the paranoid android, thanks! <3 It can be done at night as well, however most of the gates are closed to the Castle, so you'll have to walk around quite a lot. The sight of the deserted castleyard will compensate the effort :)