@Emil Pinlac - we're based on the Bay Area so prices may be a bit lower in Sacramento but we've done a few projects in a similar price range as @Whitney Hill mentions - $150-200K of project costs for ADUs ranging from 500-750 sq ft.

I can listen to books and educate myself on whatever I want while at the gym, in the car, etc.A couple I'd recommend to you based on your post are..FLIP - How to Find, Fix, and Sell Houses for ProfitThe Book on Flipping Houses How to Buy, Rehab, and Resell Residential PropertiesThis book is not currently available on Audible but a must readThe Book on Estimating Rehab Costs - J ScottBigger Pockets has become one of my best resources.

And, while that's out of their control, modeling a conservative base case that assumes the same exit cap, or a few points higher can make all the difference. 

@Mason Myers Pricing will vary quite a bit, based on several factors.

I personally have never had any architect or structural engineer bid any of my projects or that of my clients based on a percentage of the construction, it is always based on time which is subject to complexity.

Quote from @Joshua Posada: Im open to other areas.What do you have in mindI'm based out of the Pittsburgh area would you consider Pittsburgh? 

Hello Bigger Pockets community.Trying to get base line number of what the average % yearly operating expense per unit is for a typical class C property, 2-3 BR on a 5 to 20 unit property.

Just based off of the rental income of the property 

Looking to refi based on the value after rehab based on rental income/cashflow (expecting it to be around $200-210k value) Aiming for $150k loan for paying off current mortgage and covering remodel/rehab costs on my propertyIs this doable without a significant down payment?

I matched this property to my investor for $195,000, she is looking at $50k in rehab and we have a solid exit on this at $320,000!