One idea, drain a quart of oil out of the crankcase, let it sit overnight in a clear jar, then visually & odor-wise compare it to another quart of new oil. You might notice the crankcase oil is separating into layers, where the new oil doesn’t.
I doubt an evap leak would be causing gasoline to get into the crankcase. But it could cause a significant gasoline odor in the engine compartment.
Evap leaks can usually be figured out by a shop using a smoke machine to find the source, if a quick visual doesn’t show anything obviously wrong w/ the various hoses and valves.