Well, it has been a while. I strained a muscle in my abdomen and haven't been doing my gardening work this past year. But I'm finally ready to start planning my next steps with the greenhouse.
The mouse problem is serious and ongoing. I've decided that the structure simply isn't well sealed enough to be a real year-around greenhouse; critters and pests just build up. (The way I build the retaining wall means that there would be no efficient way to block out critters.)
So I'm planning to use it as a two season (Spring and Fall) greenhouse with a removable cover. During the Summer, I'll use it as a giant trellis for squash and other vines, with shade loving crops underneath. In the Fall I'll put the plastic on to extend some things, then take it back off over Winter to let the cold weather deter pest build-up, and then recover it in the Spring for seed starting.
I'll still use the IBC/Radiator set-up to balance temperatures when the cover is up. When the cover is not up, I'm thinking of using the IBC as a giant Kratky hydroponic tank!