So I'm running a bit behind schedule. (Big surprise there). In the meantime, take a moment to revisit all those wonderful childhood memories of swapping out 5 1/4" floppy disks while trekking across America with a team of oxen and a covered wagon. If you are especially lucky, your entire party may even die of dysentery along the way ...
The Official Oregon Trail website kindly links to a ready-to-play emulated version of their 1985 game for Apple II.
The Oregon Trail Apple II Emulator
Official Oregon Trail Website