Wish I had advice as to the risk of this creating a problem during your trip, but I don’t. I just don’t know. But below is some info. One thing you might do is check a local dealer or a dealer on your route to see if they have a fuel rail pressure sensor in stock you could pick up and just keep with you. If you break down, might give you a shot at having a local garage install it to see if that’s the problem. I think they’re about $100 or so.
There are two subcodes in the manual. Both seem to say to check the wiring for the fuel pressure regulator circuit and the fuel rail pressure sensor circuit and, if okay, suspect the fuel pressure regulator or the fuel rail pressure sensor. DTC code descriptions attached. This is from a 2014-2015 manual.
It’s my understanding the fuel pressure regulator is actually an integrated part of each HP fuel pump on these cars. The HP fuel pumps are along the passenger side of the engine below the head.
The fuel rail pressure sensor is a separate part that screws into the end of the fuel rail on the passenger side.
I haven’t accessed any of this before, but I think you can get to the fuel rail pressure sensor through the passenger side wheel well by removing the wheel well cover. I’d be trying to replace the fuel rail pressure sensor before I did anything with the fuel pumps.