3x PBP finisher but sadly no races across the continent. OTOH maybe it's a good thing based on how I felt after 1500k at Natchez Trace.
Coast riding though, plenty of that down the Washington and Oregon coasts.
Rando, anything over 400k, is mostly about what's between your ears. If you get to the PBP start line, you have the fitness, and you likely have a reliable enough bike to get you to the finish. If the carbon wheels help the grey matter, then go for it. 10x more important than that: don't dork around at the controls. Also more important: stay on top of your fueling. Carbon aero lightweight shiny stuff doesn't do you a bit of good if you're standing in a line you shouldn't be standing in.
But seriously, if the carbon wheels provide enjoyment or motivation, that's gravy.