Six flags over Texas from 4pm- 9pm with a 6 week old?

UPDATE: As much as I need to get out of the house I decided to stay home with my 6 week old. My 3 year old will still be going with her Dad, my Dad, brother and my Mom.
My little family (Husband, 3 year old and 6 week old plus myself) My Mom and Dad and Brother are suppose togo to six flags over Texas theme park this Sunday for Father's Day. They aren't going till 4pm since we have the baby and the earlier day will be way to hot. We will have a mini fan, goto the in door shows and walk the shops with the baby.. My Brother, my Husband and my Dad will more than likely go ride the bigger ride and my Mom and I will take my 3 year old to ride smaller rides and can take turns riding with her. Do you think this is doable with baby (who is also breastfed) getting to hot? Any tips to make it where she doesn't get to hot?