You could have a few things driving the cost:-Location - if the house is more remote the contractor will have higher costs to get out there (gas, lodging, limited resources) or if you are using a local guy he might be higher because he knows there are fewer competitors -El Nino - the roofers we use are all busy because people are rushing to get work done before the rains hit.  

I've been looking to expand in a way that will both benefit the construction side of the business along with growing in a newer space of business.

We have been in business for over 20 years and are NARPM members for over 15. 

Figure out your business plan and exit strategy as you accrue capital and keep an eye on the market it’s hard to tell when the time will be right as the market is in flux.

For older demographics, consider the availability of medical centers, entertainment, and restaurants.Buildings/Permits: Assess the city's growth compared to previous years.Determine if the city can accommodate future supply.Government Regulations: Examine the city's efforts and the type of businesses they are targeting.

I know of only a few people that own rentals as a secondary aspect of their primary business.

Lots of folks priced put of Fishtown are moving north and Richmond Ave had been slowly bringing in new businesses. 

It's the best way to gain experience, work with buyers and make money while you're growing your business. 

This would allow you to calculate if the ADUs will add more value than the cost to add them. 

I also have a plumber across the road that I allow to use my lake access in exchange for labor when needed.