An hour by train from London, the town of Lewes manages a rare double act: it sits inside a national park and is itself officially recognised as an urban arboretum. Accredited by ArbNet, the international arboreta network, the whole town counts as a green space — fitting for a place wrapped by the 618-square-mile South Downs National Park, with the River Ouse curling past tree-lined paths and houses spilling over with balcony gardens.

History runs deep here too. Lewes Castle, built in the 11th century, still looms over the High Street, and the Saxon and medieval lanes branching off it are lined with buildings spanning the 11th to 19th centuries. The castle keep is open to visitors and offers views over the town and the downs, with the adjoining Museum of Sussex Archaeology adding context.

Yet Lewes feels nothing like a museum piece. With a population just under 16,000, it supports a busy calendar of markets, plus a dense scatter of cafes, pubs and independent shops. Antiquing is the headline pursuit: W.F. Bruce on North Street specialises in restoring stately English clocks and old watches, while the Lewes Flea Market is a rummager's dream of jewellery, furniture, artwork and collectibles — shoppers warn you'll need serious time to get through it. The Lewes Arms, a wood-panelled pub pouring Harvey's ale for more than 220 years, makes a good rest stop between shops. On the fourth Saturday of each month, nearby Ringmer Village Hall Market adds cakes, honey, knitwear and candles to the mix.

The national park on the doorstep is half the appeal. A 3.5-mile loop from Southease station follows the River Ouse to Monk's House, the 17th-century cottage where Leonard and Virginia Woolf lived and wrote for around 50 years — the interior and gardens still hold many of their belongings. Southease is 15 minutes from Lewes by train, or you can walk in along the Literary Heroes Trail. For something more adrenaline-fuelled, two paragliding schools near Glynde station (five minutes away) run one-day taster courses with Fly Sussex, plus tandem flights over the English Channel cliffs. Drivers can pick up the South Downs road trip, one of Britain's best scenic routes, which passes wineries and villages near town.

Practically speaking, Lewes works brilliantly for car-free travellers: the town centre, castle and trailheads are reachable on foot, by bike or by rail, and there are plenty of hotels and inns within steps of the High Street. It suits a weekend crowd — Londoners after an easy escape, vintage collectors, walkers and anyone combining a coastal trip to nearby Eastbourne (20 minutes away) with a dose of countryside. Come for the shops and castle, stay for the downs and a pint under low beams.