Working on the exhaust now, I have some aluminum honeycomb coming a and ordered some extruded aluminum from Misumi to build the frame to hold it. For the exhaust fan I am using a fan setup that was pulled out of an old Spectra Physics laser diode power supply. A little over 200CFM. I took a piece of 1/2 acrylic and cut it to fit in the garage window frame and used the laser to cut the holes to mount a dryer vent exhaust to it.
Need to mess around with finding good feed rates for this, I was cutting slower than I needed to here.