On the T stat, sounds like it was running over 205 F on the blacktop... at that point the 195 stat was full open so changing the stat would not help.

Blacktop radiates heat plus you were not travelling fast enough for good ram air (20-30 MPH not enough, 40-50 should be). At that speed you depend on the fan to help move air.

Sounds like fan + shroud might be the place to start. A thermal clutch fan + matching shroud is hard to beat... with a more aggressive fan since you are fighting cooling issues. Bouchillon has a nice clutch and 6 blade fan or the JY + AP store will work.