But even if you use fancy software, that's not where the secret sauce is.  

This is the secret sauce.

There is no secret sauce method, virtually every home for sale is on trademe.  

I ran the numbers with rough and likely mildly pessimistic estimates of total rehab, based on paying $425 total to have it in good enough shape to keep 70% of rent, then assuming loan cost of 6.5% (definitely pessimistic since the last two were around 5% for me), and they aren't all that attractive-  If $425k total in-Rent for $4200 total =$2940/month using 70% rule$2535/month P+I for $340k borrowed at 6.5% for 20 years $1500 insurance plus $2740 Taxes=$353/month for Taxes and insurance$2890 total MTI =Marginal to no cash flow, $7800 per year in paydown- so about 10% on the $80k I have in, Then market gain leveraged X 5- This is the big wild card, and the one where I may be less optimistic than the rest of the crowd. 4% sustained yearly gain would make the whole thing seem really attractive all of a sudden- but I don't see our economy expanding in the middle class enough for this to keep happening for much longer :(a 1% cheaper loan saves only $200/month- still weak sauce cash-flow wise. 

Kevin,I can't give you the magic sauce recipe you might be looking for, but can share with you some general advice that might be helpful.  

There is also a bit of secret sauce to acquiring the park for a fair price based on how it performs, and also estimating how you can improve on that.  

It's not that we have internet issues very often, but a few times a month is more of a hassle than I want when I'm not making money on it.If you share it, get a Wi-Fi router with Tomato or WW-DRT (whatever it's called) and limit bandwidth on each device so there's not one device hogging the network.

Some are lucky.Some are lying.Some are really good at what they do.Too many factors to nail it down to a secret sauce that can be repeated by anyone.

Simple, the underlying fundamental of compounding returns combined with leveraged funds, it's the secret sauce that makes REI the profit generator it is.