Acquiring the 130-acre Goddard College campus was an impulse buy for New Hampshire developer Mike Davidson, who told Plainfield residents on Monday night that he hadn't even known it was for sale as recently as two weeks ago. Davidson moved quickly. Last week, he put down $3.4 million for the purchase, which he said will be final at the end of November, and met with town officials to learn about the campus and the town. On Monday, he turned up at the Plainfield Opera House for a selectboard meeting with his chief of staff, Tim Sidore, to share a few details about his vision. "We don't have specific plans; we're developing ideas," said Davidson, who owns a large development company called Execusuite in Lebanon, N.H., and said he spends winters in Mexico. He also owns a Lebanon commercial and residential property management company, Ledgeworks. On Monday, Davidson praised the beauty of the former agricultural estate. "There is a campus where we can paint a bigger picture," he said. Davidson's bid is the third that Goddard trustees have accepted since they announced in early April that the college would close. The first two prospective buyers backed out, but Davidson on Monday pledged to stay the course, saying he has the money to fix up Goddard's historic buildings. He said he wants to create affordable housing, offices and art studios, but emphasized that it's too early to know for sure what he'll be able to do. Davidson said he hasn't inspected all the buildings yet. He's captivated by the possibilities of the college's wood chip boiler plant, which provides heat and hot water for most of the two dozen buildings on campus, saying he cares deeply about using sustainable energy sources. "We're blessed to already have the chip plant," Davidson said. "You've got heat piped around the campus. It's a brilliant, efficient heating system." [content-2] The future of Goddard’s campus has been up in the air for months, even before the tiny alternative liberal arts school closed in September. The college, established in 1938 on a former agricultural estate called Greatwood, had 1,900 students at its peak in the 1970s, but by last April, only 220 people were enrolled. The school stopped hosting students on campus in the early 2000s, and started offering short on-campus residencies instead. Last year, trustees announced the residencies were going away, too. Many alumni and community members…