And if you've lived in it for 2 out of the 5 years prior to selling it then you get the $250K primary exclusion. 

I am able to work as a travel doc, and she works remotely in tech, and we plan to use our combined incomes to put towards REI, as well as keeping our cost of living reasonable!

I am trying  to purchase a multifamily house , outside of the city where i live it wis about 150  miles from my location ,  how do i figure out the demographics of the area and also the medium income around the area where i am planning to purchase . do i need to look for any big stores/shopping malls or any govt offices around the area to see if the place would be ideal for purchasing the property for renting it .

I have a ton of experience and in investor relations so I live PPMs, OMs, Sub Docs & more. 

Has anyone lived there in the past 4 years?

First off  you have a CRIME FREE /Drug Free addendum on each tenant that lives in your rental.If you notice suspicious activity or have reports of the same you give tenant notice of high traffic / volume of people to unit as notice to cure.. if this continues or you see or smell drugs you give notice of non-compliance and lease termination. yes you can ask police for advise.. but your main goal is to limit the calls police have to make to your property so you don't want to be listed as a nuisance property. but if the issues warrants it yes call the cops and if a neighboring unit is worried tell them to call the cops sometimes you have to have a record of police calls to verify the issue so you can write up infraction for eviction action..

I say this because while I plan to live on our rental income in retirement I am hoping that our other investments can cover the cost of inflation. 

I used to live in Castleton before Bank One moved me to Tampa in 1996.

Duplex in West Adams area.Asking $830000Spanish style house on a nice street with similar houses, mixed single family and duplexes.2 units total, 2b/1b and 1b/1bAbout 1600 sq feet totalI think 2 bedroom could be rented for at lest about $2500 and 1 bedroom for around $1800-2000.I will live in one of them though.Also has a 2 car garage which can be converted into ADU.Has parking plus street parking.Both units need reno.Considering that all units need renovations and I will live in one unit and rent the other and that at some point I will convert garage into ADU. 

You absolutely charge higher rates if it's in close proximity to a University; they're paying a premium to live close to campus.