The cabin is in the Poconos -which is in far NE Pennsylvania people and where Uncle Nicky lives is waaayyyyyy western PA, like bordering Ohio. Probably at least 5-6 hours away.
Honestly, given that they are in the Poconos at Labor Day, the trench doesn't alarm me. What does is that there's supposedly a park and a walkable Chinese place somewhere close to a cabin in the Poconos. My family has one and trust me, you don't walk anywhere but to your neighbors' houses. At least where our cabin is, anyway, but the Poconos is pretty folksy.
I went back to watch some missed scenes from last night and noticed that when Rebecca is in the Chinese restaurant panicking about losing her phone, she says she needs to call "her son". This show uses a lot of subtle ambiguity to throw off the viewer. Since Randall had been calling her frequently during the Philly Thanksgiving day out, they want us to think she's looking to call Randall when she gets lost at the Chinese restaurant. Really, she's in the Poconos somewhere trying to get to the cabin where Kate & Kevin are celebrating. We find out that Kevin (maybe everyone?) isn't talking to Randall.
I think that when Rebecca is saying she needs to call her son, she's actually talking about Kevin.