San Diego is a beautiful, magical place, and one of the best places to be houseless in the US.
In general, homeless people are everywhere, camping is easy, cops are chill. But there is a high risk of being robbed if you're not super careful.
Take the trolleys. Get a $2 Pronto card and put $3 on it. Ride the trolley wherever you want, never scan the card. Occasionally security will ask if you have fare, scan your card, not take any money, smile and walk off.
Seaport village and the surrounding pier is a great area for artists, buskers, etc. Lots of people sleep there.
Meals daily at 11am at 12th and Imperial (go in the office first for an orange card) Dinners Monday Tuesday and Thursday at 3rd and Ash at 4. Social services at both.
Check out the Linda Vista area for tons of woods to camp in but watch out for thieving homebums. Balboa park is the same but even more crowded.
Go to Ocean Beach for an entirely new experience, lots of vagabonds and hippies of all kinds, tons of art and music, drum circles on the beach Wednesday nights, open mic at the Template Thursdays, random bonfires and pizza on the beach, free weed from magical old bums, etc.
There's a place called Sharia's closet that will give you a custom bag of nice clothes in your size.
Take the blue line trolley to the balboa park transit center. From there, it's a short walk to the 101N onramp, and you shouldn't get hassled by city cops here.
Nomadwiki & Trashwiki
Check Nomadwiki for info on accommodation, showers etc. or Trashwiki for dumpsters...and share your wisdom :)