Airport layover taxi to Mutianyu wall

I arrive at the Beijing airport on Sunday morning at 5:30 am and my next flight leaves at 14:30 pm. Will it be easy for me to get a regular taxi to drive me to Mutianyu? How much will it be including the road tolls? And should I take another taxi back or let the driver wait for me at the wall (what would be cheaper)? Ar should I go with a tour for about 700 RMB? Thank you!