This seed spawns a Woodland Mansion pretty far away, but the Mansion has a slightly larger third floor (and thus more interesting rooms). To reach it, all you need to do is turn around once you spawn, and start walking -- keeping the mountain to your left. Once you pass the mountain, just follow the river until you come to a land bridge between two rivers. From there, just head straight until you hit a swamp. The Woodland Mansion will be at the edge of that swamp on the left side.
This seed is actually good despite how far away the mansion is, because you can spend some time exploring before you get to the mansion and preparing to fight the mobs inside.