You are going to love this hunt.
Good glass makes it more fun - not necessary, but you can really reach out...you might consider pairing with an Ollin adapter and your phone for video.
Gun choice - so many opinions and options - I've had very good success, including aoudad, with a .300 Win Mag, using Federal Terminal Ascent (200 grain). I agree with the other posters - get comfortable shooting at distances and various types of rests/sticks/bags/bipods, etc.
You might not need to be in great shape - but it could definitely be a difference maker - consider a MTN Tough program - Aoudad live in nasty country...
If you can, bring a friend - it is a great group trip - often many targets - the challenge is getting in range and closing the deal - you are going to see some great animals. Also, consider spending some extra time in this area, most people aren't aware of the rugged beauty of this area - you might be surprised that it is Texas.
Fort Davis/Alpine/Marfa area is awesome. Free range aoudad. Others can disagree with me, but this is the equivalent of Iowa Whitetail, Utah Elk, Vancouver Island Black Bear, Kodiak Brown Bear, BC Mountain Lions or Limpopo Kudu and so on...this is where the big boys live...and they move the needle way past the high fence options in other areas....
And yes, everything down there wants to poke you...look twice before you sit or put your hands on the ground!
Have a blast.