Advice Needed: Contractor selection in Houston Heights

[Victor Mondragon]

BP Nation, I need your help!

I am working on my first deal in my own backyard. (literally!)

I am in the process of building a garage apartment at my primary residence in the Houston Heights area.  It is going to be a pretty simple 24x24 2 story structure with a 2 car garage on the first floor and a 576 sqft 1bed/1bath apartment upstairs.  Nothing fancy, nothing too complicated.  

I called 4 different contractors that I found doing work in the area.  3 of them are larger construction companies that told me the build would be priced "starting around $150k" or more.   The 4th bid I got was from a guy that is pretty much a 1-man show that specializes in garages, garage apartments, and barns.  He initially quoted me 90k turnkey for the build when we spoke on the phone and I was ecstatic. 

 I interviewed him last week and he seems to pass the eyeball test (25+ years of experience, demonstrated good working knowledge of construction and permitting, seems to have solid trades working for him, etc), but then told me that the 90k he quoted me did not include "fixtures" or appliances.  (I assumed appliances were not a part of the deal, but "fixtures" was a curveball).  I asked him for a formal bid that drew out exactly how much everything would cost as well as what IS and ISN'T included so that I can properly budget for this project, as well as 3 references from recent jobs he has completed.  

We met on a Thursday and he asked me to give him "Through the weekend" to work on sending me a bid.  I didn't hear from him so I sent him a follow-up email Tuesday night asking him where his bid was.  He replied asking to give him until Thursday because "things got busy with the rain and all."  Thursday came and went, and still no bid. 

My question to you all:  I haven't even got a bid from the guy and I'm already losing patience.  Should I take his inability to meet 2 deadlines as enough evidence to run for the hills and hire somebody else?  Is this just what its like working with general contractors that work for themselves?  This is my first deal, and my first time getting a loan for around 100k and that is a ton of money for me.  I want this project to run smoothly, but I can't afford $150k for this project.  

Any feedback on this situation would be greatly appreciated.  I don't know if my expectations are too high or if I need to heed the initial warning signs and take a different route. 

Thank you all in advance.