Helping the poor.
I would set up the best set of public restrooms and showers/washing machine areas in the world.
I would then set up micro atm accounts, for those homeless willing to be identified, so that they have a place for stashing and getting cash.
The third leg is a phone/message system, set up with the ATM, where homeless can check for messages for odd jobs, etc. A website for potential employers to set who is available, (work history, skills) would be nice. To join this system, part of that ID check would be verification of American citizenship. I would have no intention of setting up anything that would encourage yet more illegal immigration. In fact, this might have the opposite effect.
One location for both, preferably next to the police station or CHP, or other very public protected place. Someone who has become homeless who is not breaking the laws, other than not having a domicile, will find these features very useful in getting re-established.
The phone/message system could be upscaled for the successful homeless to a limited cell phone.