I am going to ditto with the going through Order. Even if you went back through at your original chapter, most of the girls are going to be unaware of who you are, not resentful of you for leaving. And once they learn that why you're there I can't imagine they'd be offended or resentful. If I was an active and an alum came back just to go through Order I'd think SK meant a lot to her.
(But I'm an all around nice person... no really!)
And I'm sure an Alum chapter would love to do it as well. My new chapter was so excited just to have me there for the Christmas party, and I was the youngest one there by a good 10 years! (The lady I was next to was from the pledge class of 84. The year I was BORN

)