NORTH CONWAY — Businesses throughout the Mount Washington Valley reported a strong Memorial Day weekend, with one business owner saying she had an “incredible” weekend with activity numbers “double those of last year on this weekend.”

According to an informal survey of its members, the Mount Washington Valley Chamber of Commerce and state tourism officials estimated that 540,000 people headed to New Hampshire for Memorial Day 2012. In the valley, most businesses told the chamber good weather, an improved consumer outlook and falling gasoline prices contributed to a strong weekend.

NewHampshireGasPrices.com reported the average price of gas in New Hampshire was $3.65 going into the Memorial Day weekend, down 18 cents in the past month and 20 cents less than a gallon than last year at this time.

Cathy Bedor of the Mount Washington Cog Railway on Monday said rides on the historic train were on their way to a record weekend.

Susan Logan, marketing director of the Conway Scenic Railroad, also said there were noticeable numbers of Chinese and Pakistani and Indian guests, as well as French-Canadians riding the trains over the holiday weekend, the chamber said in a news release.

Karen Tolin of Raft NH and Muddy Paw Sled Dog Kennel told the chamber that the Memorial Day weekend was “incredible,” adding that whitewater rafting and summer dogsledding numbers are “double those of last year” because of good tourist numbers and a rise in overseas travelers, specifically from Saudi Arabia.

On the downside, Peter Gagne from Saco Canoe Rental Co. told the chamber business was down by 15 percent over last year for the holiday weekend, perhaps because of the 56-degree water in the Saco River. But Gagne said this year was the first time the company ever rented a river tube in May.

Marketing Director Thomas Prindle told the chamber Sunday was the strongest day of the weekend at Attitash Mountain Resort and Wildcat Mountain, with visitor numbers up 19 percent at Attitash over last year.

Corrine Rober, owner of Margarita Grill in Glen, said the restaurant had a strong leap in sales for Memorial Day weekend this year, and that sales through Sunday increased by 25 percent over 2011 after Margarita served more than 200 meals.

Hotels also reported strong guest bookings over the weekend, the chamber reported, and the survey showed that advance bookings are up for the summer and fall.