Costco suggestions

Mayfield Heights, OH store near Cleveland.

Camillus - Township 5 (now open!)
DeWitt - Shoppingtown
Chittenango - former Ames/Brand Name Deals
Clay/Liverpool - Build from scratch on NY 31 or the Shops at Seneca Mall (former Price Chopper) on County Rt 57.
New Hartford - Former Price Chopper
Colonie - Former kmart (Albany County)
Fulton - Former kmart
Auburn - Former P&C
Cortland - Riverside Plaza
Palatine Bridge - Former Ames
Latham - Latham Circle Mall
Oswego - Former Tops
Rochester (Irondequoit) - Medley Centre
Batavia - Former Lowes
Other locations TBD.

I've only been to the Costco in Arlington, VA (DC area).  Almost went in Dedham, MA (Boston suburb).