I have played Victory at Sea solo. It flows pretty well. And since no actions are considered simultaneous it works fairly well.
I have played the "Battle of the Denmark Straight", "Air Action Bismarck", "Night Destoyer Action Bismarck", and the "HMS Rodney and King George V versus the Bismarck" all as a mini-campaign.
"Battle of the River Plate" Also makes for an excellent solo game, since it is a 3 - 1 ration scenario.
I have also played a Coral Sea/Midway type US Carrier air group strike against a Japanese carrier task force. Landed some good hits but was unable to sink any of the carriers.