At what time does your flight arrive?
A driver to take you to Mutianyu and then to your hotel is around 700RMB. Absolutely no need for a guide. I thought that Mutianyu was closing earlier (17h) but they must know.
Next day, a decent guide for a whole day is 800 to 1000RMB per day. On day 2 program is light. Not sure why they take you to Fayuan temple given your limited time.