e.g Worthing to Southampton on the 700 bus, takes approx 3 hours on a Saturday.
Leave Worthing seafront at 08.06, via Chichester (09.48), and arrive Southsea, Clarence Pier at 11.09.
Places to visit: Royal Marine Museum, D-Day Museum, Blue Reef Aquarium, and the two piers.
Return, Southsea, Clarence Pier at 15.19, via Chichester bus station (16.46), and arrive Worthing Marine Parade at 18.33.
If you wanted to venture further afield, eg from Worthing to Canterbury it would take longer and neccessitate a lay-over.
Leaving Worthing seafront on a Saturday at 07.27, travelling on various buses via Brighton, Eastbourne, Hastings, Camber & Folkestone, reaching Canterbury at 14.53. After an afternoon sightseeing, find a b'n'b.
The following morning (Sunday), leave Canterbury at 09.30, arriving in Worthing at 17.00.