I'm sure there are many ways to structure this kind of arrangement but it's just another suggestion that shouldn't cost you much and will get your message in front of more people than just using your own vehicle.  

Agree ahead of time that this is a business and that family stuff is not part of it.  

Focus on the job I've got and try to make connections and get ahead?

I recommend if your exchange is remotely within those dates, to go ahead and get them on the calendar with advance reminders set up because we all know that anything can happen that could delay a closing and with accountants now filing online, mistakes are easier to make.  

Or she might tell you there are 4 people in line ahead of you, and each person will add another 20-30 days to the time line, assuming nobody ahead of you buys it.

I have no idea how effective that is, but at the local REIA meetings I went to all year last year there were always 1 or 2 vehicles parked in the lot with the ads on them.

But, no need to get ahead of yourself with your "gross profit" talk.

I let my busy life get ahead of me even though I know what real estate can do to someone's life.

I do agree that for all parties a fixed price estimate is best (you need to know how to estimate properly).To be successful as a GC, things like getting a large deposit, making sure you are always staying ahead on billing and are spending clients money and not your own, marking up all costs at least 20% to cover OH&P, billing appropriately for change orders, not to mention staying up to date on latest building methods and continuing education, are the minimum requirements to last in this business.Of course you have to keep construction costs as low as possible when you are rehabbing a real estate project.  

Welcome to BP @Michael Oldani it sounds like yo have a head start in this business.