By my count it's definitely further to go east. You can get to the lake in about 8 days, but then you've got to cross the mountains (along the base, not over them)... looks like about 18 days from the lake to the "scar".
The other way, if you get back in the canoes, you can cross the south end of the swamp, then head to the Wreck in about 8 days, then hack through the jungle for about 12 days. Better chance of getting lost going that way, sure, but just put more people on navigating, and you should be fine.
Speaking of which, I need a general consensus on which way you're going, and then I need the usual checks. I'm gonna go for two checks per character, with your idea about how the check helps your travelling. While perception is good to keep an eye out for trouble, if you do too much of that without enough survival or other navigation-type checks, you might get lost, even if you avoid trouble (or at least avoid surprises).
As always, feel free to ask if you don't understand what I'm asking for.