I'm toying around with a timeline where the POD is the Yongle emperor choosing his second son as his successor, rather than his first, making Ming China a little more exploration-focused, at least for one more emperor's reign. I want to have a ship land in the Americas, and I know plenty of alt histories have done this (usually with Zheng He, obviously), but I'm trying to work out the specifics and am just unsure of how probable it would really be.
If a ship did reach somewhere, what could motivate them to establish a colony? And what could make the colony last, especially since the Ming is already on pretty thin ground, financially. Where would they have to land on the Pacific coast to find gold, or some other valuable-enough resource to maintain contact to the point of a permanent colony being established?
The butterflies after this would be, of course, extreme - a new source of gold or silver would mean Spain and Japan don't have the stranglehold they did in OTL, possibly leading to a stronger and longer-lasting Ming. And old world diseases would have a 60-some year head-start in the West of the continent. And a bunch of other things my brain isn't even reaching at the moment.
But all of that is dependent on the feasibility of the colony in the first place. It's been done, but does it ever make sense?