I feel for you.  Our house was built in 1923 and over the years we've kinda reworked and redone a lot of it.  The big project came back in 1994 when we added on a dining room, great room, and bathroom, along with adding on to the basement under the new addition.

Where the divorce almost came into play was when the wife announced part way into the project was that she wanted the kitchen remodeled too and wouldn't give up.  My dad was an outstanding cabinet maker in his day and I did pick up the know-how from him and we still had all the tools, so that cut down on the expenses a lot.  Cabinets were high then already.

Ours turned looking quite good, but the point I'm trying to make is add in AT LEAST 20% or more to the estimated cost due to the wife upgrading the plans.  I should have learned that lesson from my folks when they built new 20 years earlier.  Any chance you can do some or most of the labor yourself?  That's what has always saved us from really having the cost get out of control.