With all due respect to Pete's point of view, I'd suggest first defining the load and then seeing if the current bike is sufficient. If it isn't, then look for something better. Not everyone tours with 15 pound loads, so the light bike that's OK for that may not be adequate for handling the final load.
Back to the OP, John Nelson's question is the first thing to answer. If the tour is a supported tour, ride anything. The truck or van can carry the load.
If it's an unsupported tour, try to do your planning now to figure out what kind of load you'll be carrying. With a typical load (I think most cross-country tourists weighed at Adventure Cycling headquarters carry 35-40 pounds of gear plus bike), you'll want at least a rear rack and panniers, and possibly a front rack. (As an aside, I'd avoid putting a front rack on a carbon fork.) Somewhere between 5 and 50 pounds there's a breakpoint where shimmy becomes a problem with a light bike, and then it's time to beef up the bike. At 40 pounds of gear, it's probably worth taking a classical touring bike (Surly LHT, Trek 520, Novara Randonee, Fuji Touring, CoMotion Americano) to have the load adequately supported and braced.
Does a full-on loaded touring bike cost a lot? Unsupported week-long AC tours seem to average about $1,400, about the same as the production touring bike above (except the Americano). The more you ride, the less a bike costs. I could afford mine, and still ride it; you'll have to decide how it fits into your budget.
Do try to test ride anything before you buy it. This late in the year you may have to make a trip to find a touring bike in a shop.