Chasing down P0456 very small leak detected. 2007 Lexus rx350

So far I have replaced the gas cap with an O.E. cap. Did not help.

Basically it could be a cracked fuel hose line or evap  purge solenoid or charcoal canister or small leak in the fuel tank.

The only clue I've been able to collect so far is it pops up driving in town very quickly but highway driving it never comes back until you drive in town again, like the next day, not if you come off the highway and drive around in town for a little then back on the highway.

It doesn't leak any fuel, at least not where I can see on the driveway. It's been cold so I haven't looked at the tank or hoses yet. I am trying to avoid throwing parts at it. The clue above has me thinking it points at the charcoal canister or a fuel tank leak because both would be blown away in the wind on the highway not allowing the vapors to ping the ecu for the error.

Any additional insight would be appreciated.

Fill it with smoke and look for the leak. Best way, you can also you extremely low air pressure and see if you can find it. Most of the usual spots can be found on forums or by engine code. 

In reply to wearymicrobe :

Is this a thing where I can light a cigar and blow smoke into one of the evap hoses or will I need a smoke machine that I can leave the system sealed up like it would be normally?

https://www.amazon.com/AutoLine-Pro-Automotive-Detector-Diagnostic/dp/B07JVT1NG2
 

Evan smoke tester. Admittably I used one to find exhaust leaks on my last truck and I rented it for a few bucks locally.