Town base on or near ROK

For a more relaxed, off-the-beaten path experience I'd opt for Ballinskelligs. It's on the Skellig Ring Road but away from the traffic of the ROK. There are ruins of an old castle near the beach - usually deserted since tours (and tour buses) don't go out there, and the ruins of an old abbey too - it's where the monks from Skellig Michael relocated when they left the island. The Skellig Ring Road is a real delight. The Kerry Cliffs provide some very pretty views of the Skelligs on a sunny day, and there's a terrific chocolate factory out there which (for some of us at least) is a destination in its own right.
Waterville is a nice little town. Since it's on the ROK itself it does see a lot of thru traffic during the day, but I would think that after the buses go home and things quiet down it would be even nicer. There's a very pretty beach side promenade that invites casual strolling, especially in the early morning or late afternoon.
You can usually book the boats from the Skellig Center at Portmagee (the ones that circle the islands but don't land) a day or two in advance, so you could check the weather & the sea state forecasts and then make your decision. The trips are weather dependent (actually, they're dependent on sea states) and they'll cancel if conditions get too rough.

We spent 4 nights in Cahersiveen, which is a little less than 10 miles north of Waterville, and found the area to be an excellent location for day trips. Castle ruins, 2 ring forts and a lovely beach (White Strand) were all nearby. We spent an afternoon in Waterville and thought it was a very nice little town. There was a park along the water where we picnicked and, of all things, a Charlie Chaplin statue (he was apparently very fond of Waterville and spent a lot of time there--they have a film festival there in his honor every year). I agree with Robert that the Skellig Ring Road and Cliffs of Kerry are wonderful, as is Valentia Island. The Skellig Experience (ie visitor's center) is there--you can see a short video showing what to expect on a visit to Skellig Michael--it might serve to motivate (or dissuade) your husband. When we were there Star Wars was doing some filming so Skellig Michael itself was closed to the public--but, from the video, it looks amazing!

Thank you both for your detailed insight! Now I'm sure we'd be happy with either location so we'll try to let the lodging decide for us.