2008 Toyota Tacoma Leaky Head Gasket

Accumulation of what appears to be old, gunky oil between the head and the block. This is right next to the oil dipstick. What really concerns me is the difference in color on the block (see pics). After researching this issue I learned that milkshake oil in the oil cap can be a symptom. I did notice this when the vehicle was brand new, but have not seen it for quite awhile (I've done all but 2 oil changes on my vehicle). I use Mobil 1 fully synthetic. Spark plugs were replaced at 58K, oil @ 5K intervals (as recommended), air filter changes at recommended intervals as well.
I have not noticed any reduction in coolant level, only a decent amount of condensation in the tail pipe, and steam until the engine is running at temp. My driving as changed lately, as my commute as greatly increased from about 20 miles a day to over 100. Engine seems to run smooth at speed. I want to say I feel it runs a little rougher at idle since I changed the spark plugs, but I'm not sure. It may just be my imagination. Toyota tech I knew briefly said he thought it sounded and felt fine.