If you can stretch it out a little, you would probably enjoy these places in B.C. Not too expensive. Might offset the cost of fuel.
http://dutchlake.com/cabinprices.htm
http://www.elysiaresort.com/photogallery.html
http://www.crookedlakeresort.ca/the_lodge.htm
http://www.wellsgraycountry.ca/visit...wgc/index.html
Not sure about beaches and the water's a little nippy. Horsefly has a little beach at the provincial park campground. Crooked caters to hunters in the fall. For sure you'd have a great time at any of these places.
Cheers!