Charlie set a 4-hour timer on her watch after she used the ATM to get the money for her car repairs. The model of watch she uses, the CASIO A158WA-1, doesn't have a countdown timer function; just a standard watch and a stopwatch that only counts forward.
A building number "9200" is clearly visible on the front of The Roadhouse diner near the roof line. The service station is just a few doors down on the same side of the road. The station is twice stated in dialog to be at "421 Route 66". Numbers 421 and 9200 would not be near each other and would not be on the same side of the road. (The two filming locations were in different towns).