Set aside 10% of rent each month.Remember you always have to save money each month because sooner or later,you will spend it on new roofs,appliances,water heaters,minor storm damages,resurface driveways or parking lots,etc.Never stop saving,always collect it and set it aside.

I will add basic updates to keep property current but that was off your list (two tone paint, modern lighting, clean/current flooring, wallpaper removal, resurfacing counters, etc.).  

. $4000 per unit is budgeted in my underwriting for renovation.Building Qualities – 6 buildings - 33,200 SF● 1 bed 1 bath – 550 SF – 8 units● 2 bed 1 bath – 700 SF – 24 units● 3 bed 1 bath – 750 SF – 16 units● Two-story● Individually metered electric, landlord paid water● Central heating and air● Copper Pipes● Built: 1975 ● Pitched roofs – All replaced in August 2007● Onsite laundry facility – Units purchased 2012● Parking lot resurfaced 2005● All units in good shape, with minimal cap ex required● 1 mile from 5 star public middle and high school● 4 units recently renovated with $100 rent increasesThis is definitely a tertiary market, but population growth is on a slow rise (1% from 2010-2016).

Is it more cost-effective to resurface the original hardwood or just get new flooring throughout?

As for the interior, I would resurface the kitchen counters (<$1000) and many of the companies will do the same for the cabinets and just change the hardware as long as they are structurally sound. 

. (;-) are you sure you are not missing a Zero on the Purchase price - $145,000)$30k for cosmetic renovation on 8 units sounds low. i just did basic to reasonable standard (check my BP blog) and it costs 5k per door. no new kitchen or bathes but re surfacing and granite tops., Viynal planks hardwheres thorough, signage and light fittings, fencing etc.

We also resurfaced the carpet stairs with white oak treads that came out beautiful.

So right now I would learn about the business, and watch for the opportunities which will eventually resurface as rates and housing prices (hopefully) come down some.  

So we then  painted the whole joint, repaired the rotted fascias, replaced the ancient AC/heater, new pool pump equipment, new concrete driveway to replace the crumbling asphalt, new landscape, updated bathrooms (resurfaced shower, nice, new cabinets/sinks, but off Craigslist), more new flooring extended throughout the entire house... even some upgraded pool furniture and a nice BBQ outdoor kitchen as we were told we are in a high end area that requires these types of amenities. 

HOA is healthy and lots of repeat renters but there is currently an assessment levied for resurfacing and painting of the exterior.