Spring things in New Castle and Rye.A trip to the Seacoast confirms that summer is just around the bend. Picnic tables at clam shacks are getting a fresh coat of paint and lilacs are blooming beside New Castle doorsteps.Saturday MorningWe were awakened by sunlight pouring in the big windows of the Bartlett Room at the 1810 Pickering House, a B&B in Greenland. Following a thoroughly satisfying breakfast, we headed lemming-like to the sea, stopping at Little Boars Head to admire the 19th-century summer “cottages” facing the ocean from their spacious grounds along Millionaires Row. We arrived at Fuller Gardens while the dew was still clinging to emerging rosebuds. Their more than 1,500 rose bushes will not be in full bloom until June, but the gardens are already lovely.LunchDriving north along Ocean Boulevard, despite the substantial breakfast, we can hardly wait to get to The Ice House on 1B, our go-to place for fried clams. There’s lots more on the menu, including fish & chips made the right way. But we had been savoring the memory of their crispy, tender fried clams since last fall.Saturday AfternoonWe detoured north to Little Harbor Road to see the state’s original lilacs. The Wentworth Coolidge Mansion itself isn’t open in May except for the Wentworth Coolidge Lilac Festival on May 28, when there are free tours, but we can still admire the first lilacs planted in the New World.Following the Colonial history theme, we headed for New Castle and Fort Constitution. It was here (then called Fort William and Mary) that the first military encounter of the Revolution took place, when a local group of The Sons of Liberty liberated a stash of ammunition, weapons and other supplies from the British.The Royal Governor took refuge on a British warship sent to rescue him from the roused rabble, and soon left his posh mansion and its lilacs forever.Saturday EveningWe had brought our sea kayaks, so we put in at BG’s Boat House for an early evening paddle around Sagamore Creek to work off the remaining calories from that mound of the Ice House’s crispy fries. On a rising tide we explore the backwaters of this meandering estuary.Dinner at BG’sBy the time we had the kayaks back on the truck, it was a bit chilly to sit on the deck overlooking the waters we’d just glided through, so we chose an indoor table at BG’s Boat House and tucked into a plate of succulent steamers. Then we slurped up a bowl of fish chowder before tackling our big red lobsters. All that sea air and exercise …Sunday MorningAnother home-cooked breakfast fueled us for walking the trails around Odiorne Point State Park, where the modern history of New Hampshire’s Seacoast began. Its “guest book” reads like a social register of early discoverers: among them Champlain, who sailed into the harbor in 1605, and John Smith, who sailed past in 1614.From the level trails we explored early farms and the “hills” that hid the World War II guns of Fort Dearborn, built to protect the Portsmouth Naval Shipyard, where 22,000 workers built submarines. We stopped into the Seacoast Science Center to meet the ocean fish in its 1,000-gallon tank.Sunday AfternoonBefore capping off the weekend with a whale watch from Rye Harbor, we communed with sea creatures in a slightly more intimate way over a plate of succulent sea scallops at Petey’s Summertime Seafood.