Really! You are needed here! What else is so important??
Ok, I think this is coming together in my head. I'm thinking the duct from the hood goes thru the abandoned door, and the fan, in it's plump plywood plenum, is outside, where it won't take up usable space and won't make the room so noisy. It won't actually be Outside, but on a sort of abandoned porch-y, very open yet roofed area. Yeah, that'll work. Especially if I can scrounge the plywood, though it's only partly about saving money; also the loveliness of USING that fan & motor. Putting it outside will allow me to put in access to the motor sheaves to adjust speed, if necessary. Would be hard to do inside. Ok! Thanks, all--PJ, take tomorrow morning off!
Will keep you posted!