Timeshare presentation, a new MR Visa card, perhaps a convert in from the Amex MR program?

Both the timeshare and the MR Visa take a while to post, of course. Sadly, there's no C&P award with Marriott. I imagine you can buy points from Marriott but I doubt it would end up making any sense for you in the long run.

There aren't many ways to convert other miles/points into Marriott points. It's the one program of the big 3 where to accumulate a big balance, you really have to stay at the hotels. HH has its reasonably fair-value conversion in from AA and SPG has a powerful earnings option in the Amex. (The MR Visa is pretty lame except for when you use it at the hotels to earn 5 pts/$.)