Welcome,
Please call the Dividend Miles Service desk and ask for the Silver or Gold challenge! This trip alone will put you very close to qualifying for Silver Preferred with the challenge.
PIT is a VERY nice airport with a full blown shopping mall. Street prices too! Some Mag rated it the best airport in the US. PHL is what it is just like LAX! If you had a US airway Club Membership LAX, PHL & PIT are amongst the nicest in the entire system.
Something to consider as you switch to US over Delta. We still have the ability to earn Preferred Status with Segments. Most of your stuff out of ATL will be connecting through one of the 3 hubs, PHL, CLT & PIT. This means 4 segments EVERY Trip! One trip every 2 weeks and you hit Chairmans Preferred with 4 segments left over. Gotta go