Ironhands, don't know the area but Imp would suggest you ride your route on the weekend, when there's less traffic to check it out. If you feel uncomfortable, don't do it. Getting hurt is not worth it.
Riding in the area of highways is always a bit dodgy, you have to take the lane and watch carefully for drivers that will overtake you and right-hook to enter the ramp. Expect it and remember that you have as much right to be there as they do.
Riding on sidewalk is not really legal, as far as I know. However, in the area of the highways, there's usually nobody on the sidewalks, so I would take it if you're uncomfortable in the lane, but if there's somebody walking, make sure to go slowly and give them right of way.
I'm not sure where your work is, but there's always an option of taking the bus with your bike for part of the way and then cycling.