We just returned from 1000 Islands where we stay in loop F at Wellsley Island State Park , it is great. I belive it will be open all year if there information is right. The loop f area has water and electric and sewer and is in and open field backed by woods for some cover. We would of liked to be going this week but it just could not make it work. I would call the office to be sure but the book from the NY SP system makes it sound like certain loops are open all year. Good Luck and have a great time.
Mike , Leslie and Heather and Maggie Canine Traveler
2001 34' Dutchstar, Ford ,Double Slide
2007 Honda CR-V Toad