Richmond is one of the most appealing places to spend a day within striking distance of central London — far enough from the centre to feel genuinely unhurried, close enough that you don't need to plan much. The town itself is attractive, with a good high street, a riverside walk along the Thames, and Richmond Green providing a handsome open space a few minutes from the station.
The real prize is Richmond Park. At 2,500 acres, it is the largest of London's royal parks — big enough that deer herds roam freely and the city disappears entirely from view. The park has been used for royal hunting since Charles I enclosed it in the 1630s, and from King Henry's Mound on its north-western edge there is a protected sightline all the way to St Paul's Cathedral, seventeen miles away. On a clear day this is one of the best views in greater London.
Kew Gardens lies just to the north-east and is easily combined with a Richmond visit. The riverside pubs at the foot of Richmond Hill are packed on summer evenings and worth finding early. Along the river south of town, Ham House preserves one of the finest 17th-century interiors in England — the towpath walk there is as rewarding as the house itself.