You should ask if you can take them on a test sail. My wife and I are the original owners of an 1986 h23. We raised 3 kids sailing on it, with many overnights, spending up to a week at a time. The h23 has good performance, is easy to trailer, launch and recover, and it fits nicely in our carport during the off season. With netting on the lifelines, we were comfortable letting the kids use the relatively wide side decks to sit on or go up to the bow (obviously wearing either a lifejacket or a harness clipped to the boat). It worked well for us in all respects and I can easily recommend the h23 for your described use. A note, we set up the main cabin bunk(floor boards in slots, seat backs laid across them) for the kids to play in underway, which they loved, but you have to fill in the void at the forward end by the bulkhead. Leaving the keelbolts exposed cost us a trip to the ER when we forgot to one time and one of the kids managed to go head first into that space. Just toss in some soft stuff like towels, blankets, pillows or sleeping bags (always good to have on board with kids anyway). On the flip side, I don't have personal experience on a Tanzer 22, but a friend who's owned one for many years seems pretty happy with it. I understand they also have good performance. So it comes down to personal preference. Good luck and enjoy.
Jim Kolstoe, h23 Kara's Boo