Great to meet you.We source from four primary suppliers: Lowe's, Home Depot, Floor & Decor, and Amazon.

Short of coming here and meeting face to face with them and come to a couple local REIA events to discuss, for those who are remote I would suggest getting into some of the NE Ohio REIA facebook groups to get some advice from locals.   

There has been being a meetup in Wboro but I'm not sure of their meeting times. 

You will need to submit a detailed permit application to the Chicago Department of Building.

I also advise participating in regular meetings with them.

The bay area has many old houses so be aware of what it will take to being them up to code and meet insurance requirements.

(The bulk of the problem is Nimby-ism and local regulations that prohibit sufficient building of new homes to meet demand.)

Have you tried attending your local REIA's and real estate meet-up groups?

Start meeting with sellers in the areas you are wanting to work in whether they be mobile homes in parks, lots and/or out on land.

Have you looked into any REI networking or meet-ups in the area?