Atlantic Watersports in Bideford can arrange kayak hire and will drop them upriver so you can paddle with the outgoing tide.
Cycle on the flat "Tarka Trail" that loops along the Estuary - bikes can be rented on Fremington Quay
Surf or Boogie-board at Croyde, Woolacombe or Saunton (boards and wetsuits can be hired on the beach at each place)
Explore Exmoor, Lynmouth and Appledore
Enjoy fresh fish brought in on the trawler (see blackboard on the beach for timings), or a Hockins ice-cream, made locally in Appledore
Take a ferry from Bideford to Lundy
Visit the picturesque fishing village of Clovelly
Enjoy a cream tea on the patio of the Commodore Hotel in the village, or in the Cafe on Fremington Quay.
Exeter is only an hours drive away for shops and restaurants
Travel into Cornwall - Padstow is about 1 1/2 hours drive, or 2 hours to the Eden project.
If theres bad weather, shop in Atlantic village or take the kids to The Big Sheep.