Richard there are plenty of fuel stops.
Cook town, Musgrave, Coen, Archer River, Bramwell Juntion ( normally the dearest) and the start of the otl. Most fueled up at Cooktown and Archer River as the most klm between these places are about 150 klm at the most.
Once fueled up at Archer River you will do the trip to Seisa no problem. If you want a Jerry can it will be all you need.
Mark