Three years ago we I did an extensive search to find bulk DEF in Alaska and came up with zip. I haven't found any up there since then. Since we spend every other summer in AK it was more than an academic exercise. I've used the 2 1/2 gal jugs and refilled them, but they take up a lot of room in the basement and are a pain pouring them into the DEF tank. DEF takes a lot of heat and time to start deteriorating, so I would not be concerned about buying the 2 1/2 gal tanks in a store, except for the high price in remote places. We've got 60,000 miles on the Bus and have had no DEF issues.
Because of this difficulty, I purchased a 15 gal farm chemical spray tank from Tractor Supply and placed it at the very rear of the Bus engine, just below the engine access hatch. The tank allows me to fill it from either side (no more entering DEF lines backward) and holds enough to get me from Montana to Alaska and return to Montana without needing DEF.
