They won't declare bankruptcy until they absolutely have to. They are looking at giving current bond holders 85% of the company, 10% goes to PIERS holders, and the other 5% goes to common stock holders. There is only 1 large bond holder that refuses to talk but everyone else is basically on board for the debt-to-equity exchange because Six Flags has turned it around. They had positive cash flow for the first time EVER last year even with the crappy economy.
Check out these articles:
http://washington.bizjournals.com/washington/stories/2009/03/16/daily10.html
http://www.coasternews.net/2009/03/15/six-flags-bankruptcy-and-you/
http://www.nytimes.com/2009/03/14/business/14flags.html?_r=3&scp=2&sq=Six%20Flags&st=cse