Throbbing in outer quad above knee I have been riding a bike that is in all honesty meant for someone much smaller than me.  I have raised the seat quite high and got it far back enough that my spine is in proper posture while I ride.

I notice (during the day at work) a throbbing pain in my outer quadricep just above the knee.  I have been riding much more in the last few days (roughly 2 hours per day) and perhaps it's just part of being in my 30s adapting to this increased demand.

Or is it a symptom of bad leg posture that could lead to something worse down the road?
As others have said, and as you said, the frame is probably too small for you which can cause pain and a bad time in general on your ride. 

I find I get pain in the Vatsus lateralis (outer quad) either when I am using too much quads all around and need to creep forward on the saddle and pull more with my hamstrings at a higher cadence, or, my posture is poor and my knees are collapsing toward the inside of the bike during the pedalstroke. 

If it's a real problem that you can't solve yourself without some third party perspective, I'd recmmend a professional bike fitting. They aren't cheap, usually a couple hundred dollars, and it's takes a few hours of your time. Some places will even have shims and heel cups for your shoes to get a really nice fit. 

If you still have pain after a couple weeks riding out from the fitting I'd see a doctor.