You can also use the CAP rate or income based approach to value the property if there are no properties like it, but honestly if there is another investor, broker, or agent that has worked the area for a while they could give you a ball park. 

I was hoping that some other forum members who did direct mail campaigns for house hacking could chime in with how they approached it.

@Ouman YouMonetized installment sale might be your only option - provided that this controversial approach works for you.

I get approach  sent letters daily etc etc by wholesalers out east .. waste of my time. .most are beginners don't know a deal from a barn door.If I lived out your way and that is the culture I would play.. but for me personally nope..

You can see it briefly as you approach the house and ever so slightly along the property line if you walk along it and look through the trees.

In the end, all your profits will go to the lawyer and you still may not have the end result you want.But your post indicates that you like the hands off approach that these units have brought you so far and that you really enjoy being passive in your investments (who doesn't???). 

I just don't know how to approach the owner, how to put together an offer, what it even means to put together an offer, or how to present it to him.

Is it just not possible here or I’m approaching them wrong?

The income approach is used on 5 unit or more buildings.

I understand you have to spend money to make money sometimes, but it can be a big challenge while going through a divorce.