I have the sign, and can get past the road crew, but how do I get past the phone guy and the lawn crew? There's nothing else I can find that will help me with that.

You haven't advanced far enough in the level to get past the guy with the phone.

You haven't explored enough to get past the lawn crew (the guys with the water jugs?) Platform games are all about exploration, trial and error. Go explore every house, inside and outside, and open every trunk of every car. Sometimes you'll find something useful that way.

As Mike suggests, note that you can enter every house in the level. Also you'll find more cars like the one that had the sign and you can open the trunks by punching them.

When you get to the post office try entering a bogus code on the keypad and remember your powers, especially ones you just got...