Private property is as easy as getting permission of the owner and securing event insurance. But, an unfinished housing development is probably owned by some corporation and you'd have a hard time getting permission or even finding the right person to talk to.

I expect it would be close to impossible to get permission to run on an unused interstate rest stop.

It's a really hard sell to get a site to open up for motorsports these days. Everyone wants to know the same thing... "what's in it for them?" At the local autocross or rallycross level, the answer is "not much" because we can't afford to pay a lot for site rental. It can be a little easier if you find an "in" somewhere. Someone who is sympathetic to your cause, and has the connections to help make it happen (even though there is little or no benefit to the site owner).

Start by verifying that the site is suitable for your purpose. The neighborhood roads are likely curbed, which will make them useless for autocross. Sanctioning for a "road course" type of event may be more expensive than autox insurance, which is relatively cheap due to autox being considered very low risk.

Unfortunately, any way you cut it, securing a new motorsports site takes a lot more legwork than just spotting places on a map.