Credit Cards, Cash & Traveler's Checks
Living near the Canadian border I pretty much split my riding between there and the US. Having learned from experience I contact my CC company to advise them that I'll be in Canada so they don't suspect unauthorized CC use.
That said, I STILL on occasion find my CC's being locked out for suspected illicit use. I carry two, but now I carry more cash and a few traveler's checks as backup.
"Rider assumes full responsibility"