Military history, scenic state parks and tasty shellfish make for a rich weekend escape on Whidbey Island, Wash.

As my 14-year-old son, Anders, scampered up a metal ladder to the gun emplacements at Ft. Casey Historical State Park on Whidbey Island in Washington last summer, I resisted the impulse to shout “be careful.” He’s as agile as a monkey, so I let him scramble about the bunkers housing the massive artillery while his sister, Maddie, 16, and I enjoyed the views over the northern end of Puget Sound. The battlements at Ft. Casey, a 998-acre marine park, were once part of a “triangle of fire” that included two other forts.The 120-year-old Ft. Casey attracts more than military history buffs. It has the restored 1903 Admiralty Head lighthouse, hiking trails, a bird sanctuary, meadows ideal for flying kites and a beach for building sand castles. It’s also a short drive to the picturesque villages of Coupeville and Langley. The southern tip of Whidbey is just 30 miles from Seattle. The tab: $175 a night for lodging in restored non-commissioned officer’s quarters at Ft. Casey Inn, and $15 for a one-pound plate of Penn Cove mussels at Toby’s Tavern.

THE BED

Ft. Casey was once home to 100 officers and 400 enlisted men. The officers, of course, had the best lodgings. Visitors can stay in one of the inn’s two-bedroom homes, which have a living room, full kitchen, upstairs bath, front porch and sweeping views of Puget Sound. Kids are welcome, but not pets. It’s a short walk to the lighthouse, bunkers and the gun emplacements.

THE MEAL

Seafood aficionados rank Penn Cove mussels among the tastiest of shellfish. And there’s probably no place better to enjoy them than Toby’s Tavern in Coupeville, which abuts the cove. My kids ate a margherita pizza ($11) at Ciao and I dined on these delicious bivalves (about 30 to a pound, $15) served in a simple sauce of wine, onions, basil and garlic at Toby’s. I also had yummy mussel chowder ($6 for a cup, $9 for a bowl) and a homemade brownie ($3) for dessert. I washed it all down with a Parrot Red Ale ($5.25) specially brewed for Toby’s at the Anacortes Brewery.

THE FIND

The view is stunning from 200-plus feet up in a 500-year-old Douglas fir in Deception Pass State Park at the north end of Whidbey Island. We booked a four-hour canopy climbing course with AdventureTerra guides Leo Fischer and Andrea Velasco. After a 30-minute introductory session to familiarize us with the awkward climbing ascenders, we were soon scaling a rope on the old-growth tree to a perch high above the ground. It wasn’t as easy as climbing a ladder, but the wonderful views of the San Juan Islands, Deception Pass and the surrounding forest made it well worth the effort.

LESSON LEARNED

Whidbey Island is popular with travelers and Washington state residents alike, so plan your visit for midweek. And definitely avoid taking the ferry from Mukilteo on the mainland to the island town of Clinton on a Friday afternoon; you may wait in line for several hours.

Ft. Casey Inn, 1124 S. Engle Road, Coupeville, Wash.; (855) 216-2204. No wheelchair-accessible rooms.

Ciao, 701 N. Main St., Coupeville, Wash.; (360) 678-0800. Wheelchair accessible.

Toby’s Tavern, 8 N.W. Front St., Coupeville, Wash.; (360) 678-4222. Wheelchair-accessible; must be 21.

Ft. Casey Historical State Park, 1280 Engle Road, Coupeville, Wash.; (360) 678-4519

Deception Pass State Park, 41020 State Route 20, Oak Harbor, Wash.; (360) 675-3767

Adventure Terra, 41020 State Route 20, Oak Harbor, Wash.; (206) 914-8613. $149 for a four-hour session.