Are there any alternatives to pressure treating for timbers exposed to elements? One county in our area is operating on the premise that maintenance will not happen so they are mandating pressure treatment on any outdoor beams. Penetrating oils are preferred but isn't sufficient for the county code. Any suggestions?

I always wondered why people treat the timbers at all. In my quest to find a job to learn TF'ing I noticed quite a few companies say the treat their timbers.
Is that a sales thing or do you really need that?
I mean the house I just finished restoring that we live in is a circa:1680. I seriously doubt anyone treated these timbers and they're still here hard as a rock 326 years later. Heck...the bark is still on some of the floor joists!

You might try to convince the building inspector to let you use
naturally rot resistant wood like Black Cherry or White Oak.

Black Locust is a great option too.