Depending on how dry the air in your room is (ie if you have a window or vents open), your frog may not last long. Then again, my house is really dry, and I have been fortunate enough to find an escapee 48 hours after I noticed he was missing.
Frogs can hide anywhere, and usually turn up when you least expect them. I would place various water dishes around the room-some down on the floor, others on shelves or ledges, and keep the lights low or off. Your frog will naturally try and find a water source, so the more you have available, the better chance he will find one and not dry out.
Best of luck and let us know what happens.