I really think the first idea could be explored more, but I think it has a really sound premise. A lot of players, myself included, work long hours. On the weekends, I'd like nothing more than to sink 12 hours at a time playing, but I do so at the risk of a rather unhappy fiance (Though at least there would be truth in advertising - she'd know what she was getting into before signing the dotted line...)
Perhaps fleeting can be done where a player either A. Hires a fleet to convoy them in their off hours, or, and I like this idea more, B. Nation NPC traffic has some scheduling aspect to it, where players can go to the departing port, park their boat, and a convoy that was already going to have half a dozen frigates suddenly has some snows, brigs, even perhaps trading vessels. Taggable in the open world, and perhaps even insurable.