[JayChicago]

"I was thinking it was blow by since I can see some smoke occasionally coming from the Oil Filler tube after long drives."

That does not seem to be excessive blow by. I get steady smoke wafting up from the filler tube when hot at idle. But the road draft pulls it out when driving. Never had a complaint from wife/kids about smell in the cabin. Maybe check out the road draft system as mentioned above.