E.C.
Not sure if you have checked this one already, but our favorite hotel near Storyland is The New England Inn -- www.newenglandinn.com -- it is very nice and not as well known by the Storyland crowd.
Also in New Hampshire is Santa's Village -- lots of fun, in the Jefferson area. May be the same issue with hotels though??
Sesame Place in Pennsylvania is great for that age. We went for the first time this summer. With not bad traffic it is about 5 hours from Providence. Maybe a little more.
In Massachusetts there are a couple newer indoor waterparks in hotels. That might be fun. Not sure the names -- search indoor water parks in Massachusetts.
Edaville Railroad does a big festival this weekend -- could do a hotel in Plymouth area, do Edaville which is in Carver, Plymouth Rock and Plymouth Plantation, etc.
Roger Williams Park is also doing their jack-o-lantern spectacular. We plan on doing that this weekend and then going pumpkin picking another day.
Another not too far destination although not as theme parkish -- Mystic in CT. You can do the aquarium and the seaport museum and there is a Children's Museum not too far from there. Only about an hour from Providence.
Good luck!