We're already there. The US has 15.6 million vacant homes [0] and only around 567,000 homeless people [1]. Unfortunately people skirting homelessness often don't have the resources to pick up and move half way across the country so you're going to need a radical proposal for moving the homeless to where the homes are.

[0] https://www.census.gov/housing/hvs/files/currenthvspress.pdf

[1] https://endhomelessness.org/homelessness-in-america/homeless...