Hello Betsy,
My husband and I visited Bristol and Bath in September 2024. We stayed in Bristol for 3 nights and visited Bath as a day trip. In both places, we wish we had an extra day. In Bristol, we visited the Clifton suspension bridge and the SS Great Britain in one day, and I don't think we would have had time to do anything else that day. If you are going to Bristol, I highly recommend that you go see the bridge too - it is iconic for a reason.
We took a bus to the Clifton Suspension Bridge and walked from there to the SS Great Britain, taking the cross-harbor ferry to get across the water. If you decide to walk from the harbor to the bridge, be aware that it is steeply uphill.
The SS Great Britain has a lot of things to see, so it took us four hours and we could have spent another hour easily. There are a lot of different areas to explore. In addition, the neighborhood of the ship is also fascinating...we walked around a bit looking at the old dry docks, there is a Banksy there and a cute little coffee stand.
Food wise, as others have mentioned, Wapping Wharf is good - we ate at Salt and Malt as I am a fish-n-chips fiend. St Nicholas market is also good, but a little out of your way, especially as time will be short on a day trip.
If you decide to overnight in Bristol, I recommend Brooks Guesthouse. Good location next to St. Nicholas Market, walkable to the Bristol Meads train station (20 mins), access to buses to different parts of the city, fabulous breakfasts.