My objective is to purchase a duplex/triplex to utilize the house hacking method.

BRRRR is my go-to method that I'd love to try but again, a deal is a deal for our first one and that's our goal right now, just to start. 

The "BRRRR" method - acquire a property - rehab it - force appreciation, and then refinance it to pull out your original downpayment plus some profits. 

We are not showing a management fee because we are planning on renting one of the units to our daughter and have her serve as the manager for the other two units (feedback on that is welcome as well).The units have been updated in the past few years and the owner is a licensed contractor who did a good deal of the work with his company (plumbing, electrical, windows, roof).We are planning on using a HML that is offering a 30-year fixed load, 1 point to cover early refinancing since they do not have a penalty to do so, an underwriting fee of $995 and a processing fee of $695. 

Which methods take the longest to master?

Hey everyone, I'm branching out and starting long-distance BRRR and wondering what methods you have found for inspecting contractors' work.

I am familiar with the different types of investing methods (flip, rent, brrr, etc.), but I am having trouble finding what is practical for me.

Details:Goal is to Owner Occupy Location: Type A *very close to great schools, downtown walkable locationHouse: 4 Plex 8 beds and 4 bathsSq Ft: 3,548Price: $425,000Mortgage: 20% down 30 year conventional Current Rents: 790, 985, 945, 910 per-month  *These seem low for this area and for the condition of the unitsOccupancy: 1 will be open for new owner to occupyInsurance: $180 per-monthProperty Tax: $415 per-monthAnnual Maintenance: $800Water, sewer, garbage, electric: all paid for by current tenants Cap Ex: $280 per-monthVacancy: $280 per-monthProperty Mgmt: $345 per-monthThe property has had many Cap X improvements over the past 6 years including, new roof, windows, refinished hard wood floors, paint, foundation work, plumbing, electric... 

How is the plumbing? 

EDIT:  Let me add that I also look at the age of the property, trying to stay with properties built in the late 70s or later to avoid issues with lead base paint and cast iron plumbing.