Check my trip report for this region. Includes many Lucca restaurants, within the walls and S of the town.

Click on my name and you will find my 3 part Italy trip report. Part II is the relevant one.

Sarzana is someplace that you might consider. Not many tourists there. The train station is in the center of town so a visit would be easy. It may require a train change along the way.

http://www.terredilunigiana.com/eng/sarzana.php

Great day trips (or possibly over night) from Lucca;

By train: Florence, Siena, Ravenna, Cinque Terre, Pisa

By Car: Montalcino, Montepulciano, Umbria, Volterra,

Outside Florence: Monteriggione/Fiesole/Greve in Chianti (places to drive)

I, too, recommend Barga, not far from Lucca and (almost) reachable by train. I say "almost" because the train gets you most, but not all, the way there. I was able to catch a bus to return to the station but on my initial arrival no one could tell when or if the bus would come by the station and the only alternative was to walk up the mountain on the edge of a winding 2 lane road. But I'm glad I did it.

If Barga becomes anyone's destination, I suggest doing what I did not, find out when the bus comes to the station for the ride uphill to the town. Both the old town and new are perfectly lovely and because, I suspect, it hasn't been overrun with tourists, the people are especially friendly. The walk up to the town was well worth the effort.

Brooke_Harron thanks for reviving this thread, I found a good restaurant for our day in Lucca, and according to Michelin, it's still thriving!