1. What should I charge to lightly clean a 20,000 sq ft building in The Woodlands, TX? Duties would be vacuum, empty office trash cans, replenish bathroom supplies & clean bathroom. There are two bathrooms in the building. This would be 5 days a week.
2. Also how long do you think it would take me to clean it?
3. Should I hire a helper?

Supplies would be provided by the building owner. Thanks!!

Are you in the cleaning business? Asking "how long" and "do I need a helper" makes me wonder if you are in the wrong business. We have no idea as to how fast or slow you are. Did you bid on this?