Just one extra day seems to make all the difference in the world. Come Sunday afternoon, I'm usually packing up my tools around 4:00pm so that I can rush the van back to storage by 4:30, in time for closing.
Each weekend it seems like I have to start over. Pulling out my tools, remembering where I left off and gaining some momentum usually takes an hour off of the first day. So all told, my two days of build time works out to maybe 1.5 days of real progress.