If you arrive and don't initially see enough activities that suit you, ASK at the front desk! You'll get an activities schedule but don't limit yourselves to that. Encourage family members to at least show up and check out an activity before assuming that they wouldn't like it. Look at the HH tourist guides available at check-in for nearby things to do, offsite as well.
We went sea kayaking through an unaffiliated company in March, mentioned by a staff member. Great time! We saw lots of oyster beds, sea birds and a couple of dolphins near our kayaks. Some of the teens had the best time when we went to Goofy Bingo, which drew a full crowd of varying ages, mostly adults! Seeing the crowd, the caller moved quickly and made some jokes that went right over the kids' heads.

The little ones had fun too.
Besides the resort's regularly scheduled activities, the surrounding area has mini-golf and boating excursions of all kinds, for all ages. The resort also offers many family activities - not just for a small age range. We went on the marsh walk with Eric and there were kids through seniors with us, walking in those huge galoshes. Our 12 yr old DD was welcomed to attend the cooking class with me and we had a wonderful time. Teens with any interest in cooking would enjoy it. Crabbing & fishing off the pier draws people of all ages, from late April through late Sept. So does Big Murgie's Den, with a weekly magic performer (very good!), bedtime stories for the little ones and a billiard table for older kids and adults. There's table tennis, horseshoes, shuffleboard and a playground onsite. The Beach House pool has a water volleyball net and a water basketball hoop.
If someone can't find something to do - they just aren't looking around enough! Even with a late winter, weeklong visit, we were never bored. I'd encourage you to keep an open mind, ask for suggestions, try out a variety of things and see for yourself what appeals most to your family. Have fun!!!