I just lock them in the head and turn up the radio, seems to work well!
We had taken a break from sailing for two seasons and are now just getting back into the routine, in fact this past holiday weekend was our first real multi day trip in three years. With the need to finish up some major boat projects this Spring we were really only taking short day trips then coming back to the marina. It has taken some time to get back into the swing of things but the kids (and us for that matter) seem to be all good again.
I think your list is good, you could add to that
-a bird book for identification
-writing, either their won stories or have them make their own "ships log" or diary of sorts, I have started doing this year and they love it, they record the weather, destination, and brief summary of what they did, what we ate, etc
Once anchored our kids really enjoy dingy rides (with nav lights on at night of course LOL) and beach combing. A trip to the nearest ice cream store is always well received
Soon I would like to get them into a kayak, I think my oldest (8) would really enjoy it, the dingy is not the easiest to row which she like to do. At the club I plan to bring down our plywood sailing dingy for them to use in the creek.
When they were younger we had a DVD player on board and it was very useful on rainy days or longer sails of 6 hrs or more, but it died and dont plan to replace it, I could always let them watch a movie on the smart phone as a last resort. They get a kick out of the Google Sky App at night, sheet I do too!
I am encouraging them both to invite one friend at a time out for a weekend, that should be interesting.
All in all, considering how busy their and our work weeks can be most of the time, I think we all enjoy just getting away from the TV, phones and most of all other people and just having some good family time. We rarely raft up with others, we mostly prefer to get away from all the crazy's. They seem to enjoy the down time too as they get older.
Hope that helps a little.