This is not the flashiest Chester tour. There is no Roman soldier costume, no ghost-hunting theatre and no pub crawl with facts attached. It is a proper guided walk, which is either exactly the appeal or not your thing at all. The step issue matters, but for a compact, well-reviewed introduction to Chester, it is a very sensible first-day choice.
What it is actually like
The Heart of Chester Walking Tour is a small-group guided walk through the historic centre of Chester. It is the sort of thing that makes the Rows, Cathedral, Eastgate Clock and old streets feel less like a handsome pile-up of history and more like a city you can actually read.
The tour is run by Chester Tourist Guide and starts outside Chester Visitor Information Centre by the Town Hall. Expect central Chester rather than a long ramble: Northgate Street, Chester Cathedral, Watergate Street, Eastgate, the Rows, the Cross and the older layers tucked around them.
What to expect
Expect a guided walk of roughly 90 minutes, usually leaving Town Hall Square at 1pm on Tuesday, Wednesday and Friday, with extra dates often available. Book rather than just wandering up hopefully. The regular public tour is a walking tour only, so admission to historic buildings is not included.
Avoid if
You need a guaranteed step-free activity. Public booking information for the regular tour notes steps on the route and says the standard tour is not wheelchair accessible. or You hate standing still while someone talks, or you prefer to wander with no facts getting in the way of your shopping.
Nearby plan
Do it near the start of a Chester visit, then use your newly acquired confidence to choose what deserves more time: the Cathedral, the Rows, the Walls, Grosvenor Museum, Storyhouse, Chester Market or whichever old pub suddenly sounds more interesting now someone has explained the street around it.
Photos
Photos from Google Places. The TTDC illustration remains the main image at the top.
If The Heart of Chester Walking Tour is full or shut.
Chester Visitor Information Centre Chester's Visitor Information Centre sits in the Town Hall and is a useful first stop if you are new to the city or want help making sense of what is available. Staff know the area well and can point you toward things you might not find on your own. Worth ten minutes at the start of a visit. 
Chester Town Hall Chester Town Hall is a grand Victorian civic building standing beside the Cathedral and the city centre. Its Gothic Revival architecture gives Northgate Street real drama, and it remains one of the key landmarks around the heart of Chester. Even if you are only passing by, it helps anchor that distinctive old-city atmosphere. 
The Coach House Inn The Coach House Inn is a polished food-led inn on Northgate Street, right between the Town Hall, Cathedral and Storyhouse. It is more restaurant-with-rooms than old-school local boozer, with breakfasts, burgers, roasts, cocktails, wine, beer and eight rooms upstairs. Use it when you want somewhere central, comfortable and practical rather than somewhere tiny, scruffy or secretly cool.