ride fences

hey pals, here comes more questions:

1. people come in to my office and ask me where the bathroom is, should I say the bathroom in “on the lobby” or “in the lobby” or “outside to your left”.....?

2. “I have always ridden the fence with my opinion of the Princess. Today, I have hopped off that fence and decided that I really don’t like her.” what does “ride the fence” mean?

3.”She’s as phony as a $3!!! ” what does ”$3” have to do with being phony?

4.can I say zap the tv off? or zap through the channel?

Thanks a lot!!!and happy posting