Easiest way is a socket, short extension, u-joint, long extension ratchet, all duct taped up firmly, in that order. Then lightly tape the bolt to the socket. Tighten, and tear taped socket off the bolt. Makes real quick work of it. Everything else is a big struggle unless you get lucky.I can't remember what I've used to get to that top bolt, but I got it fairly easily.
It was either a ratcheting box end, a wobble extension, or a flexible extensio