Traditionally I have had a hard time doing just a bit of work. I tend to prefer doing loads of work at a time, nearly overwhelmed with it. I want to get eep into it then be done all at once. But when your life is made up of hour long chunks and you must operate around the fickle naps of a small person...it can be challenging to find those long stretches of hyper-fixation. So, I’ve been forced to work in spurts, like a grown up, or a responsible person. Or some combination of the two. I’ve been slipping out to the apartment in the evenings to put in one stair or maybe two. I got the posts roughed in. They’re extra long and they’re held in place with screws instead of bolts, but it’s close enough for me to mark the railing and the bolt holes before I take it all apart, cut the grooves and drill the holes. 
I’ve been making good progress on the apartment by taking this approach. Likely better progress than I would be making if I did it only a weekend at a time, full out. 
It makes me hopeful for other projects I might do, an hour at a time. Like clearing a bit of the forest, or building another woodshed, or finishing the middle room or Roby’s room. I want to do some built-ins in those rooms, and I feel a bit overwhelme by it. 
Chipping away might be the best path out of feeling overwhelmed.