Credentials: bought a house and refinished the oak floor in 6 rooms and a 2 hallway and it looks good. I had a similar experience. I wanted to play it safe and started with the orbital. After 8+ hours and having barely done 100sq.ft, I became frustrated and worried I wouldn't get done in a reasonable time. Drum sander is the way. Did 5 rooms faster and better looking than it took the orbital to do 1. Belt sander the edges. Always go with the grain! Wear a dust mask.

The best advice I can offer is gently lower the sander as you start moving and slowly lift as you approach the edge. Always go with the grain! You should be moving when it's engaged. I did 3 total passes with 60, 100, and 180. Anything within about 20 grit of those is fine. Belt sander the edges similarly. Start with a room or area that will get seen the least while you figure it out. I'm happy to answer questions.