In reply to Mark Kemball:
From Hull, you could follow the Trent as far a Nottingham and then the Trent and Mersey Canal to the Midlands - T&M to the Shropshire Union/ Llangollen and then follow Offas Dyke or the Severn as far as the South West. Following the Severn might be shorter, but not as pretty. An alternative might be to head for the Grand Union canal south of Leicester and then eventually cut across through the Cotswolds towards Bristol.
sorry, wrong "reply to..."
Post edited at 09:00