Are there reasons, save for the lack of bike lanes and the posted speed limits, for being forced on to the sidewalks or side streets? I regularly ride on shoulderless roads with 55MPH speed limits without any issues (not counting the occasional close pass because that can happen anywhere). I just run adequate lighting and keep an eye on my mirror when I hear approaching vehicles.

Now if it's heavy traffic that's the problem, I'd probably go with the side streets before I took to the sidewalks. I have no problem taking the lane, but I wouldn't want to cause backups during rush hour.