Yes, I like to get some mileage out of the winter season too, but our patio doors let us do a few of those things. What I would like even more than a green house is a garden room that I can walk into through my patio doors, and grow lots of tomatoes, spinach, lettuce, herbs, and lemons without even having to go outdoors. LOL
One good crop for us is winter wheat. Plant it in October, it gives some nice green to look at in the winter, and harvest around the first of June which still allows for an additional crop to be planted and harvested. The large amount of stalks left make a really good contribution to compost.
I like your idea of a garden room right off of the sunporch.
I have been moving my gardens closer and closer to the house as I age. (80 years young.)
The next thing I want is raised beds.
I would also like to hire a student/gardener to assist me this year.
Whom should I call? I can’t pay much.