You'd get the materials into space the same way that we get materials into space right now, we'd have to use the current inefficient model in order to create the structure for an efficient model.
As far as cabin fever, I've spent about 90 days out to sea stuck in a damn ship with no port calls, living in a shared berthing where my private space is about the size of a large coffin. With "comfortable" living spaces, small amounts of privacy, and a good internet connection it would be easy to spend 3-6 months in space, the biggest hurdle for a healthy crew would be living in low gravity. This could be handled by creating a large rotating cylindrical station where the berthing/everyday activities are on the outer walls while all the 'heavy' lifting could be done in the center which would still be a low gravity area.
As far as location I'd put the maintenance/cleanup about 1,000 miles out, the launch station about 48,000 miles out.