Find a really good cleaner - Try to find a legitimate company with processes and systems. 

This is because you do get an economy over a SF (same roof, same systems, one insurance policy, tax bill is spread) but by and large the tenants will treat this place as their own.   

Heating/Cooling - having central air or mini split system versus nothing/window units and electric baseboards can definitely sway your price.

I have been reading some posts and there seems to be a grading system on properties.

Set up your system for pre-screening- many people have used Google forms for this with good success.

How feasible is it to convert the heating system from oil to electric?

I know how to do comps, estimate rehab costs, and give the seller different ways I can buy their house depending on their situation whether its cash, options, lease options, subject to`s, seller financing etc.So, bottom line, if I can get sellers contacting me, I am very confident that, if their is ANY potential to do a deal I will find it, I just need to implement a system. 

So now you have a former carpenter evanluate an electric system or an former electrician evaluate a cracked carriage beam... - sometimes almost comical, if it would not be so serious.A great inspector is professionally trained in this field (not as a contractors), uses software and has a systematic approach to evaluate a home, identifies all problems correctly, but can also explain the real world consequences and not refer for everything to "further evaluation by a qualified contractor".

Humidity levels in basement is high at 64%A/C was 40 years of age, not functionalSigns of Ice damming on the garage sheathingFurnace is 19 years of age, unit didnot fire when turned on at the thermostatThe incoming 3-wire electrical systems is considered out of dateNo GFCI outlets anywhere (including in Garage)Walkway has cracking and settlementGarage floor, concrete has typical cracking and settlementBasement floor, has signs of cracking and settlementKnob and tube wiring in the home is considered obsolete and may pose an increased fire hazard.

The biggest things you want to look at in the inspection report are the roof, foundation, and moving pieces (hot water heater, HVAC, plumbing system, and appliances.