This is my first post on FlyerTalk. By way of background, my travel is all personal travel, and I am Silver Preferred with USAirways. I use my miles on Star Alliance awards to Europe and the Caribbean.

I'm looking to book a tour from Buenos Aires and need RT flights from PHL. As I see it I have three options, and I need help in deciding which makes the most sense:
1) If I book the air with the tour operator, they'll put me on LAN with a cost of approx. $1100. Miles accrued on LAN won't do me any good on Star Alliance, so I'm getting no added benefit with this option.
2) As of this minute, I can get RT flights on UA for 55,000 miles.
3) I could pay approx $1600 RT on UA and earn roughly 11,000 miles.

I'd really appreciate some feedback. What are your recommendations?