We finally got around to finishing up the greenhouse. The biggest part of that was building some shelves. I kind of wanted to just buy something but couldn't find anything that would maximise the space. And I'm glad I built them - they were only marginally more complicated than assembling whatever we bought and they look pretty great in there I think. We just used 2x4s so they are sturdy and cheap. And I finally got around to weather proofing the whole thing as best I could - spray foam and silicone in the gaps and weather stripping around the door. It is still not completely sealed but I can tell I made a big difference.
Now I still need to really 'figure out' the best way to use the greenhouse. The stuff I planted in there did ok but not super, I am hoping I just need bigger containers. Right now I am trying some lettuce and spinach in there, we'll have to see if it stays warm in there long enough for them to grow.