I think if your Hvac controll are leaking, it could cause this. You might want to take a look behind there just to double check.
Yeah access can be a pain with a stock airintake system. I forget how much room I have around the intake manifold because of my CTA (hotair, lol) intake.
I would do a visual inspection of the hoses, that will mean bending and looking for lots of cracks in the hoses. Any one that seems even questionable replace (vacumme hose is cheap) just do one at a time so you don't mix up connections. I would go for the cheap scope and listen as well.
Sometimes if you follow the PCV line to the back side of the engine, that hose has problems. You can see it easy from under the car hooked into the intake manifold.
