This is very hard to ansaw only real way examining Compitition and there backlinks quilty and getting a idea how much it cost beat them and then the domain quilty and how much to beat there in stats.
Some niche use 30k backlinks got to be careful the more popular the niche the more it cost to beat compitition with backlinks
You need a solid audit on top 3 Compitition at least to give any budget needed for any project
Real essate must be huge these days.
You might get away with long-tail keywords and sub keywords.
Main keywords forget it
If your going to base each home address as a website keyword then that grate can work.
But advertising the business name as a real essate where the money comes in.
Hope you understand
Your need to be hot hot hot at keyword research 100%