I finally received my general visitor visa refusal letter. It is as I suspected. Not enough evidence to convince them that I would return after the 8 weeks.
In hindsight it looks like I possibly should have also included the letter which gave me leave of absence from work, and then explain since the letter, I had resigned.
I also should have included a sample itinerary to show that I had researched and intended to purchase a return ticket. I think without it, it looked like I might not have intended to return.
They wanted more clear ongoing ties and commitments to the US as well as economic ties to the US. They were also confused about my living situation. It seems they thought I lived with my parents, which is not the case. But I do live in a property that my parents own (it was my grandparents home) and I have lived here 13 years.
So I am satisfied as to why I was refused and I think this alleviates the worry about the fiancee visa.