There will be information within your PIR group about rental cars and hotels as well as within the Discussions in this group and PIR Reference Information and also in the information that comes with your form letter. Sarge is also a great resource. He is OldSarge on here. You might also check on Sailors attending A School in Meridian, Mississippi or Meridian Mississippi A School family&friends. What rating (job) is your SR going to A School for? There are groups for all but 2 of the ratings with A School there.
Only your Sailor will know his/her flight details for sure and they could change even in the last week. Many Sailors flying out to A School fly out the next day, but flight availability may delay that until Sunday or later. Those with flights later than Sunday usually move over to holding at the main base and have Liberty much like those staying in GL for A School. My suggestion is that you plan to leave late Saturday or on Sunday. That will usually allow you to have the most time with your Sailor and spend time with him/her at the airport prior to his/her flight. If you find that your Sailor leaves later, you can then decide about changing your weekend plans.
(Group names and member names within this reply are clickable links.)
You can join the group, Logistic Specialists (clickable link), and they may be able to give you an idea of how flights have worked recently and what to expect while your Sailor is there.