Well there are lots of options. But you will need to do your research. There are one or two that offer shuttles. Some have outrageous parking fees at the hotel and parking at the stadium is usually expensive .. Is she participating? If so there are usually some sort of package pricing you can get. What time if the year are you going? If Six flags is not operating and it's in between Football and Baseball seasons pricing won't be too bad. If you are not having to oay normal stadium parking prices it may be best to stay more towards I20 and drive to the stadium.
@Lace:
will be: April 13
Lace, where would you stay?