I think the 60 day window for completing 12nts for Diamond status is very reasonable. I'm essentially doing my 12 days between June 14 and July 5th, which is the last day I can qualify. I had to cancel a stay early on in my challenge so I snuck a three say stay in. It can be done and relatively cheaply, particularly if you stay at HPs of SSs. I've just kept my eyes open and got some great rates at the GH SF and Mar Monte for a west coast trip and am doing a staycation at the Bellevue over July 4th weekend. I'll achieve my 12th night on the very last possible day, but then that's my way.