you clearly cannot insert yourself onto private property...
That basically just leaves public property. If that is forbidden, then it basically becomes a crime for you to exist.
Another alternative is needed. Sadly, most shelters are mostly full, most of the time. What is the next option?
Where do you live that the shelters are full? In my neck of the woods shelters forbid drugs, alcohol and smoking, and they are never full. The homeless would rather do drugs and sleep on the street than sleep inside.
What is the alternative? That is very simple. Not in the city and not on private property in the country. Go outside of city limits and sleep in the woods.
The real problem is that there is no one to beg from in the woods, and your drug dealer is far away, so they want to be downtown.