First, bear in mind that some of the repeating NPCs can be people that they take with them on the ship. This won't work for EEVIL types, but a variety of people who occasionally get the PCs in trouble or embroiled in local plots might be do-able.
While travelling the planes sounds like an interesting premise, you'll probably want a long-term conflict as well as the short-term episodic stuff. Perhaps the PCs are bounty hunters trying to capture a powerful spirit of the river, which "leaps" along the river from one villain to the next (but cannot possess anyone who does not come in contact with the river). The person gains a spirit familiar and a bunch of new power, upsetting the existing balances of power and causing chaos, which the PCs try to put right while capturing the spirit.
The spirit essentially teleports along the river, while the PCs have to sail. This means that there is often a warm welcome waiting for them and the spirit has had time to begin disrupting things and setting plans in motion before they arrive. The spirit shouldn't be too terribly clever on its own, but may occasionally team up with clever or devious villains.
If you go with this idea, you may want to give the PCs a way other than direct confrontation to force the spirit out and on to the next episode. Something so that if the spirit is working with an evil tyrant the PCs can't get close to, or some such, they still have options.
Anyway, just a couple thoughts off the top of my head for ways to give continuity to the game while keeping the episodic and plane-spanning nature.
. . . . . . . -- Eric
While travelling the planes sounds like an interesting premise, you'll probably want a long-term conflict as well as the short-term episodic stuff. Perhaps the PCs are bounty hunters trying to capture a powerful spirit of the river, which "leaps" along the river from one villain to the next (but cannot possess anyone who does not come in contact with the river). The person gains a spirit familiar and a bunch of new power, upsetting the existing balances of power and causing chaos, which the PCs try to put right while capturing the spirit.
The spirit essentially teleports along the river, while the PCs have to sail. This means that there is often a warm welcome waiting for them and the spirit has had time to begin disrupting things and setting plans in motion before they arrive. The spirit shouldn't be too terribly clever on its own, but may occasionally team up with clever or devious villains.
If you go with this idea, you may want to give the PCs a way other than direct confrontation to force the spirit out and on to the next episode. Something so that if the spirit is working with an evil tyrant the PCs can't get close to, or some such, they still have options.
Anyway, just a couple thoughts off the top of my head for ways to give continuity to the game while keeping the episodic and plane-spanning nature.
. . . . . . . -- Eric