1. Is riding on the sidewalk in your county legal?

2. It is a judgement call on your part. Do what you feel safe with. Don't risk your safety.

3. Is there a safe way to get on/off the sidewalk? Or would you have to slow way down to get up there and maybe get unpredictable and confuse the drivers? You don't want to do that.

If it is 4 lanes you should be able to take lane without too much trouble. On my return route from when I escort my wife to her work on bike, there is a 2 lane ~.25 mile section of roadway. It is 35mph posted, no shoulder, but sidewalk available.

I take the lane because it is faster than the sidewalk, and, as I understand, all counties in Maryland have outlawed riding bikes on sidewalks, except for Montgomery county.

It seems to work fine for me. Remember, the cars have 3 other lanes to use. Unless the mph is high, I just take the lane.