Tofte there is a Holiday
Grand Marais there is a Holiday, or Devil's Track gas, resort priced on the end of the lake
There is gas up the Gunflint (Forget the name of the place, but you could make it up and back from Grand Marais if you really had to)
There is resort gas at Crooked Lake Resort, right next to Trestle Inn
There is resort gas at Knotted Pine in Isabella (Fill here before heading to Ely if you plan to make that run)
There is gas in Finland at the gas stations right on trail, you are pointed off the NSST on both ends of town.
If you plan your stops right, unless you are going to Ely, you can buy gas station gas all weekend.