Your surrogate will need to be in Villahermosa at least a 4-6 weeks prior to the birth. By month 7 you should have provided their per diem for living expenses and made living arrangements. By this time you should also book flights for surrogate to Villahermosa. Wait until month 8 to book your flights due to change fees and unknowns with pregnancy.
Book your accommodation at Month 7 also. One booking site recommended is www.zyanrooms.com. Their rates are much less than sites such as Airbnb.com .