Summary: Sometimes it's nice to just sit in your room.
Commentary:
1. This is a sonnet.
2. It has the word "sonnet" in it!
"Within the Sonnet’s scanty plot of ground;"
3. I agree that it's nice to have a small room to sit in. I've told my wife I would live in our shed if I could. I remember my dorm/first apartments, and it was kind of nice that all of "your" space was one room. Made it easier to keep things organized.