There is a lot to know and you don't want to introduce too much new risk.

Your examples and explanations help a lot to clear up the original question, specifically clothing items.Do you recommend I keep a record, separate from my P&L, of purchases that may be less-than-ordinary, such as a cargo box to carry tools in my truck, or car seat protector covers (to protect my truck seat from getting dirty from tools and other items), etc.?

Big response Sounds like you have a lot to say about it. 

There's a lot to it and many people set it up and then don't want to do all the extra steps. 

There is risk when doing real estate investing, but there's a lot to gain if done right.

That will have a lot to do with the discrepancy you are seeing in price.Treat every market you go to with the same principle as the game monopoly.

It takes a lot to design, get the deliveries, put everything together, and make sure it's ready for guests. 

Rates would have to drop a lot to reduce your payment hundreds of dollars after only a year.

As soon as the house is built, I want to start a new build on this lot to sell as a spec house, budgeting approx $450k build cost, sale price is estimated $750k, supported by comps.

Thanks for the excellent questions bud you really added a lot to the thread!