Another update
We're planted up now and the shed is almost done. We added window boxes today (no pics yet) and tomorrow I hope to trench a water line to it. The old greenhouse is torn down and the floor area has yet to be removed so I can plant my squash that are still in post. We had a couple of heavy storms and everything seems leakproof and wind safe glad to report. Had to beef up the fence with a few wires to keep the darned dogs out too.
I think some of the advice about ventilation is spot on as even with the doors open it's getting really hot inside. I'm investigation the differences between temperature activated window openers vs a fan on a thermostat.
Next we'll mulch it all with well rotted manure and then, EAT!