I've been lurking for some time, but finally decided to reach out. I recently took a job which requires me to travel for about 5-10 nights per month in California, and I've been trying to plan ways to maximize my rewards. As a current platinum member of Hyatt and Diamond with MGM's Mlife program, I've been loyal to their hotels, but the region I'm travelling to only has Marriotts (I'm a fan, but just haven't been in locations that have Marriotts available or simply couldn't pass up the rewards from my other programs). I've been reading through some of the different aspects of the Marriott rewards program and trying to figure out how to optimize both my rewards, bonus points, etc.
I'm not currently interested in obtaining a credit card to earn rewards, as I use a corporate card for all my travels and expenses, but I am intrigued by the gold/platinum challenges. Are these restricted to only holders of Marriott Rewards credit cards? I'm currently booked to stay 3 nights this coming Monday so I wanted to plan accordingly.
In addition, I book my hotels through hotels.com (In order to earn free nights after 10 stays) and didn't see any official disadvantages to this or advantages through the Marriott website I would be missing so hopefully I'm not messing up there!
Also, any other tips to start earning with Marriott, maintain my various statuses, and optimize my earnings would be greatly appreciated!