These deals are risky and complicated.

My leverage was my intimate knowledge of housing systems and construction techniques and my willingness to apply time and energy to the problem when I didn't have money.

But, generally, this is not very accurate.Anyway, there are a few more techniques they can use, but this gives you an idea of how they should go about it.So, as to your specific question, YES, you can most definitely dispute the appraisal if you think there are legitimate reasons to.

The one and only time I've heard Dave Ramsey address the idea of "good debt" and "bad debt" with enough time given to make a complicated point, he talked about how difficult it is, specifically in real estate, to precisely calculate the risk of these investments. 

I have since put everything back on ebay and have sold it all, getting most of my money back. ( Very proud of myself for figuring out a way for a broke *** red neck idiot, to get basically a free Real estate investing education which so far has made me a buck or two,)    :)     Even today when I feel I need to get current in trends and techniques I go to ebay for some easy listening material, but I've found that most of it is just rehashed fluff from the origional gurus from my early years.

If the plans are super detailed or complicated forget about it. 

You are making it more complicated than it needs to be.

@David G. your making this WAY more complicated than it need be. 

Something tells me you won't be working 4,060 hours to do so - 80 hours a week year round.If it is a more active rental model that it is not considered "rental" income, then you would need to put in at least 100 hours with that being more than anyone else (employees, contractors, management company, etc), or you would need to put in at least 500 hours.So your "quick" question is actually fairly complicated. 

This home needs some rehab and she was concerned it was going to complicate her effort to sell it.