All of this is nuanced & complicated which is why I don't believe any single calculator exists. 

Much less complicated / expensive than building from the ground up. 

It's not impossible to do a 1031 exchange out of a property while carrying back a note, but it's complicated enough -- if you're going to make the deal attractive to him, find out if he plans on looking at a 1031 and come prepared with information to help him navigate the hurdles that come with the seller financing. 

Nevertheless, it will be a bit complicated. 

You can do it yourself; the process isn't terribly complicated and doesn't require much technical skill, but it is a lot of physical labor, and you'll probably want to get friends to help.

You have quite an opportunity if you play it right.MikeYes it is both simple, and quite insanely complicated.

If I didnt have time to learn it, clearly I wouldnt have time to make something so complicated be successful. 

Yes, if the price was wrong or the rewiring of the house was needlessly complicated and expensive.

In most cases, neither is warranted.Warning: I am not an attorney, and this can be a complicated topic.

So it is very complicated.