Am adding s small greenhouse “6 x 10” this summer so we can do a better job of growing from seed and wintering over.<<<
If possible, build at least a 10 x 10’ greenhouse, for the small ones will change temperatures too fast and are almost impossible to keep in the range you want.
For me, they didn’t make them big enough, I prefer a leanto type attached to the house, so both change heat and cool air and with barrels of water or other passive solar heating in the greenhouse.
I have worked with both styles over the years and love the attached ones.
Your grandmother was a wise woman, making money is possible even today, as there is often ads in the free cycle group for “come and get it today, as we are moving”, and some of the things exchanged are interesting.
When we moved up here, we started going to the one near the casino area of the county, once we found 27 sheets of plywood, stacked high, someone had torn down a construction building or fence and hauled it to the dump.
The Master Gardners are a wonderful source of information, it takes a lot of learning to earn the title.
LOL, I laugh at the greenies, and their Organic this and that, for it was around long before they found it.
Mine will be a lean to next to the corn crib/garage. It will have two doors one to the outside and one to the crib. Crib has large doors and windows to keep the air flowing.
Plan on collecting rain for water that will be connected to water storage in greenhouse and will be erecting a small windmill that will produce electricity to power that structure and the log cabin/guest house.