Hey flappy, I read a really insightful article about this in GQ.
Take a look:
Tent City, U.S.A.: GQ Features on men.style.com
Two things I took away from this "investigation":
1. Tent cities are more civilized than you think, in terms of user friendliness. Simply show up, pitch your tent and try your best to establish yourself as a NON-target. It's inevitable that you would encounter "seedy" people at every turn. BUT you are safe from meddling police officers, social workers and the general population. This is because...
2. You have strength in numbers if you colonize with other homeless. Although there is no concensus of unity among the homeless, there is the
appearance of unity that is respected by the civilized world because it means you are containing yourself to one general area, rather than sprawling out. It really is like establishing a small, quasi-politically soverign community.
$150 per week seems quite sufficient to keep you happy, IMO. You could even treat yourself to cheap hotel rooms every now and then (for the breaks between sleeping in tents and in parks). Also, that's plenty of food and beer money. The only other important thing I can think of is to mind your health and cleanliness.
I wonder about the prosepcts of being homeless all the time. It's one of my greatest fears. Even though my family has a lot of money and would never let that happen, I believe in mentally preparing for it.