How interested are you in history? f you are wondering about whether you should go to the Roman Baths, then my hunch is that you would probably prefer to spend the money somewhere else. That said, as a local who gets free access, I rarely hesitate to drag visitors around when they visit. Somebody has tried really hard to make to put the exhibits/artefacts into context. If you've ever sat through an episode of Time Team and enjoyed it, you've a fighting chance of enjoying a couple of hours at the Roman Baths
[Just to clarify in case there was any doubt, you MUST NOT swim or even dip your finger in the water in the Roman Baths. The officials are worried that you'll catch some sort of disease. In contrast, they conduct all manner of tests at the Thermae Spa to avoid lawsuits].
The HoHo bus is an optional extra on a trip to Bath. The City centre itself fits comfortably into a square mile (probably much less, but I've not measured it). If you were thinking "oh, but I wanted to do the Skyline walk or visit Prior Park, send me a PM and I'll double check the local bus service; the route changed recently).
Another option for the slightly lazy (but sensible tourist) would be to get a taxi to take you up to a viewpoint and then walk back down the hill.
Pubs, like restaurants, are a bit of a personal choice.