I have a section that sound similar: 4 lanes, no shoulder, high speed, a lot of semi traffic, up a hill. In this one instance I use the sidewalk. This is a section along a retention pond, so no driveways to confuse entering cars, and I slow down when I get to the one cross street. Though even there, I only rarely see a car turning onto or off of that cross street. Once I get up the hill and across the train tracks, I move back onto the street. I'm on the sidewalk for maybe the equivalent of 4 blocks. For me this potential "illegal" usage of the sidewalk is more than made up for with my sanity.