LIVING THE BRAND: After pedaling 110 miles in one day during last weekend’s Pan-Mass Challenge, Lance Armstrong made his way to Nantucket for a little R&R. But Nike’s favorite Tour de France winner hadn’t exactly gone belly-up when spotted chatting with children Wednesday at one of the island’s sleepier beaches. Fresh from a pedal with one of the guys, the soon-to-be 40-year-old wore a white Livestrong bike shirt and black bike shorts. “He wasn’t majorly conspicuous, but he also wasn’t totally inconspicuous,” said one onlooker. “And he was humble.” While his pal lamented the 11-mile post-beach trek that awaited, Armstrong told a fellow Pan-Mass-er that this year’s $34 million cancer-fighting fund-raiser had been his first one. He wasn’t the only politically minded cyclist in the 5,300-person pack — Massachusetts junior state senator Scott Brown and its senior one, John Kerry (who was also unwinding on the island), also went the distance.