Is there any way you can 'hotel hop' short term? You just need a night/stay inbtwn the others to not qualify as one stay. Go for the Gold challenge, as I think that's 6 stays & will get you most of what you'd get w/ Plat.

Alternatively, you can call Marriott Rewards Cust Svc, explain the situation, & see if they'll grant you the status based on your upcoming 60 day stay. Make sure you've made the reservation (easy to cancel if you change your mind) so they can see you're serious & not just blowing smoke. Be polite when asking.

Good luck!

Cheers.