Tetbury is a compact Cotswold market town with steep lanes, antique shops, and more serious sights nearby than its size suggests. Its streets have the usual warm limestone and old coaching-town feel, but the town is not just pretty stonework. Highgrove, Chavenage House, Westonbirt Arboretum, and the Market House give it a real day-trip spine.
Market House anchors the centre, with narrow streets dropping away toward the old wool town lanes. Highgrove Gardens, the private gardens of King Charles III, sit just southwest of town and open for pre-booked tours on selected dates. Chavenage House adds Elizabethan architecture and guided tours with a human touch.
Tetbury also works well with Westonbirt Arboretum, one of Britain's great tree collections, about three miles away. If you only have one day in the southern Cotswolds, Tetbury is a sound choice: town walk, garden or house tour, then an arboretum ramble.