hi john, obviously the biggest issue here is your UGPA. you're addressing everything the right way (alternate transcript, career advancement, etc.), but at the end of the day, it's going to be tough to get into a top tier / elite program. also, schools such as wharton and chicago which put an even greater emphasis on IA will be particularly challenging. i do, however, think you have a shot at places like cornell or yale, which are great prgrams but not typically considered part of the "elite" mba programs.
my advice to you would be to pick 4 or 5 programs with a large amount of breadth among them. and to focus on schools that value team skills and leadership as opposed to strict intellectual horsepower. from there, i'd get super crisp on WHY you need this mba, but more importantly how your experiences will benefit the school. to me, the biggest asset you bring will be your career progression. it's quite impressive and b/c it's in an analytically rigorous field, you will offset your low UPGA with it. you just need talk that part of it up to remove any doubt that you can handle the work.
ordinarily, i'd say it's not worth taking the gmat again unless you thought you'd crack 750 from a 700 (b/c a 700 is already solid). but given that low GPA, it might be worthwhile in your situation. i wrote this article that might be helpful: http://www.thefirstread.com/should-i-retake-the-gmat/
also, just so you know, the marathon thing can be a red flag in your essays if not addressed properly. b school is super social, so if your idea of a good time is to spend hours by yourself in isolation, then the adcom starts to get worried about whether or not you'll fit in socially. i was on the adcom, and that was the case for us.
hope that's helpful,
Former Kellogg adcom member, offering a new approach to MBA Admissions Consulting.