For years, fans of “Maine Cabin Masters” have watched Chase Morrill — along with his sister Ashley and the rest of their crew — breathe new life into weathered cabins across Maine. This summer, Morrill and his wife, Sarah, are inviting travelers into one of his most personal renovations yet: a restored bed-and-breakfast in Monmouth. The property — 15 minutes from their home in central Maine — was one the couple had driven past for years, but it was never on their mind as a business opportunity.