As part of using components, consider making very simplified proxy components to stand in for the complex components like your columns. If you make the proxies with the same relative origin and axis locations as the complex ones, you can easily swap one for the other using Select Instances and Replace Selected in the Components window.
Also make sure you eliminate any unseen geometry. If details you are drawing won't be seen up close, make them simpler. The bead along the length of the crown molding doesn't need to be made of a large number of segments. Eight will probably do. If the insides of closet doors won't be seen, they don't need to be detailed on the inside.
It's fun to see the materials as you go but resist the urge to paint as you build. Save painting for the end.
By the way, keep up on correcting face orientation as you go. It's a lot easier to fix it as you go along than it is to go back and fix it.