You and your fiance need to keep in mind what a trying experience building a home is. It is one thing to act as the general and have a crew of subs throughout the project and another thing to be the general and do the work yourself. If you work full time, the house will suffer, and be very delayed, and only the strong will survive. Secondly, housing costs obviously are much different from east to west coast. You being west coast, I'll talk No. Cal, average contractor costs are 150.00/sq. ft. When you start adding trim, stone work, etc. the 150 rule doesn't really apply. That is where you will save money if you do it yourself. We are almost done with our house and without the land cost, our 2016 Sqft house will havecost about 240,000. Also, if you don't need financing you can get away with the add on approach or building the shell as big as you want and only finishing the first floor, but if a lending institution is involved they want a finished house that is sellable if necessary. By the way, 2 years 2 months into the process and still speaking. Good Luck.
My $.02 Wife of Norcal Sam, Teresa