If you don't have additional information, it is most likely the mileage is legitimate and you can use it.
The answer to your question about for AGI or from AGI is from. Deductions for AGI are taking into consideration to calculate what the AGI is. A few of them are:
Certain moving expenses;
One-half of self-employment tax;
Penalties on early withdrawal of savings;
Tuition and fees deduction,
Deduction for contribution to an (IRA); and
Student loan interest deduction.
Deductions from AGI are Itemized Deductions, listed on a Schedule A. Her education expenses qualify as "business related education", as defined in Pub. 970 (http://www.irs.gov/publications/p970/ch13.html#en_US_publink1000178673). If you look in the Business Deduction for Work-Related Education, you will see she meets those qualifications. Therefore, her expenses are listed on a Schedule A.
As far as what is deductible, I would say everything. You will need to note two things.
1. 50% of what you spend on meals is deductible, so her meal deduction would be $550, not $1,100.
2. Mileage is calculated using the business mileage rate. For tax year 2009, the rate is 55 cents. The dollar amount on her mileage deduction is $880.
Please let me know if I can assist you further.