We lived in our house when our first floor floors were sanded, stained, and sealed (3x). If I remember correctly, sanding and staining only took a day. We had our contractor coat with polyurethane first thing in the morning when we left for work. We let it dry for 12+ hours (this was during the summer and we cooked on back deck after work) and were able to tip toe across the floors. As long as the floor isn’t sticky, you can step on it, but I would limit my steps. I rememner one or two prints in the floor that the contractor easily buffed out.
We moved our own furniture so I can’t weigh in on that.