Don't mean to disagree but you would not get an oil leak from the head being loose or the exhaust manifold. Especially in the top part of the engine. If it were leaking around the base of the cylinder then you'd be on the right path.
I would check your oil level to make sure it has not been over filled. Then, clean the head of residue and drive it a short distance until it is at operating temp. Let the car sit overnight then check for oil around the valve cover gasket.
I will bet oil is puddling on top of the head within the valve area. When you park it the trapped oil seeps through the valve cover gasket then down the heads. The next time you drive the car the air over the engine blows it on you and the windshield for a while. Once it's gone the misting stops. This would explain why partway through your trip you changed glasses and no more mist.
If you determine this is the culprit it may be just loose valve covers, a poorly seated gasket but more importantly have the dealer check the drain passages from the heads down to the crankcase, there's a reason why there is excess oil in the top end.
It's good to have the dealer do any repairs but in my experience, the more troubleshooting you do the more likely the problem will be resolved.
