refilling O2 bottles on the road.

Mountain High has a discussion on their FAQ page regarding different sources/types of Oxygen and confirms that it is all the same.

As others have stated, the best solution is to rent a bottle locally and return it when you leave. May be prudent to call ahead and reserve one. Having two aircraft bottles works well. Swap out full for empty and refill at your leisure.

Also concur that large high pressure oxidizer bottles and transfill systems need to be treated with much respect.