However, the fact that you're thinking about this really puts you ahead of the game and if you're thinking this way you probably have a good head on your shoulders and will be able to navigate through life pretty well.

A good strategy is to offer to pay the person (something nominal, like $250.00 to $500.00) just to spend a day with them and "look over their shoulder".  

Also I can kinda look over his shoulder as the project progresses.  

A loan is another possibility, which puts more of the risk on your shoulders.

Mine is a bit high but I have had seven knee surgeries , one shoulder surgery.

It looks like you have a good head on your shoulders and great goals for your future.

For the doors just put the width of the door to the nearest inch as it doesn't matter (Reality is your front door is 36", your bifold a are 60" and most of the interior doors are 32").

We did one where just about every door frame was 1/4inch out of a std size door width & the heights varied from 78.5" to 83". 

@Mark Tomsick the San Diego REIA clubs are a great source to learn and rub shoulders with experienced investors.

Is there any law for minimum width for stairway?