@Cecil: I'll probably have to get used to the extreme summer humidity in the summer, but that doesn't last forever. I won't miss Hawaii at all. I'm a country boy that got stuck over here due to my career. People over here just aren't friendly like in small southern towns.

I had planned on using a good quality stain such as Sikkens or Cabot's. But since I'm going for that old rustic look, it was suggested by family and the contractor to consider using diesel. The diesel/motor oil combo was the widely accepted method, I guess mainly in the South since most on here have never heard of it. I'm thinking leave out the (used) motor oil since that would give it a darker appearance. My brother will spray a small section on the inside of the barn to show me how it looks since the inside will be covered with insulation anyways.

@DD1, you have my attention now with what seems like a valid concern with the odor.

@Cecil: I would also be interested to know what stain/sealant you've used and your results. I understand different stains can have different levels of success in different regions.