I pack butter in a wide mouth one or two cup plastic bottle, a recycled peanut butter jar for example.  I pack olive oil in a small plastic water bottle with pull up nipple top, also pack cooking oil this way.  Recycled water bottles seem to be the least likely to leak from the cap.  I sometimes bring a little solid shortening (like Crisco) packed as I do the butter.  It all depends on what I think I will be cooking.  All of these are slid into additional plastic zip lock bag to prevent any leaking into the pack.  Butter is the most likely to spoil or melt on a two week summer trip; but I have never had butter actually go bad, it has melted tho.
Lard or shortening is the least likely to burn when frying things as it has a higher temperature tolerance.  Olive oil and butter have the lowest temp tolerance.