Plan a day
Canal and castle: a slow half day
Out on the water at Colt Hill, then the towpath to King John's Castle.
Start (boating season)
Galleon Marine, Colt Hill
The family-run boatyard where you can hire a rowing boat, kayak, canoe, paddleboard or small electric boat by the hour. It's closed in winter, so out of season just start on the towpath.
Or
John Pinkerton canal cruises
A 50-seat trip boat run by the Basingstoke Canal Society: a slow way to see the canal. Check its sailing dates first.
Read up
Odiham Castle (King John's Castle)
The story of the eight-sided keep, Magna Carta and the siege.
Afterwards
The Mill House, North Warnborough
A Grade II-listed watermill pub with gardens around the millpond on the River Whitewater.