It sounds like an early cancer, doesn't it so it will be much easier to treat. Signs of recurrence - I think you need to ask the surgeon that. I've had a couple of recurrences (I'm still alive and kicking) and they were picked up in routine follow ups. Of all my friends in the head and neck cancer world I am one of the very few to have recurrences from tongue cancer. My original cancer was brewing for years before it was diagnosed and I often wonder if that is why it has come back a couple of times.
After your treatment you will be followed up closely and can discuss signs to look out for. Yes, it's a really good sign there is no cancer in the nodes. You will feel much better once you've had an appointment and have a treatment plan. Then you can get to work eliminating the cancer.