There's a guild trader just outside of Shornhelm(?) (Some large city in Rivenspire...) that has nothing but large pikes FILLED with cheese in his stall.
In AD run to Reaper's March. Go to the public dungeon Vile Manse. Farm every container and food item in the house. Because it is a dungeon, there's no stealing. Enter the basement and opposite room to ladders for cheese. The house has no enemies, but be careful in basement.
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Sentinel in Alik'r Desert also has a guild trader with very easy to steal cheese (just hop into the tent behind the merchant). A lot of Guild vendors have the spiked cheese, just not all of them are easy to steal from.