The canal towpath Bath to BoA, did it dozens of times with the children when they were small. You can walk it in about 3 hours.
Definitely Bath to BoA or the alterantive I suggest below.
If you want a more interesting route than simply cycling there and back, incorporate the Two Tunnels cycle path
A popular thing to do is to cycle out on the two tunnels route as far as Midford (if you want to go to the Hope & Anchor) or get off at Monkton Combe (Wheelwrights Arms also a good pub) and then cycle back along the canal (or vice versa).
It is all reasonably well signposted and/or locals will give you directions.
If you did plan to join the canal at Sydney Gardens and it looks far too muddy, you can also access the towpath (where it has been resurfaced) at Beckford Road.
Thank you all for your super comments.
Weather permitting (!) we'll try the Two Tunnels route and link up with the BoA and either head to Bradford on Avon or head back to Bath. Really looking forward to it :)
"Weather permitting...". There are 2 long tunnels on the route you are going to try.
I would do that leg when/if the weather is windiest or wettest. as a fair amount of the route is in cuttings or sheltered by trees.
If the weather really is vile (and there aren't loads of you), you can probably squeeze your bikes onto the train back from Bradford. Or just sit it out in a pub!
Hired our bikes from Bath Narrow Boats this morning and had an amazing few hours cycling clockwise from Bathwick Hill round to Dundas Aqueduct where we watched the canal boats, grabbed a tea and cake at The Angelfish and continued our cycle. Did the main tunnel and then the second but due to time constraints decided to leave Two Tunnels route so came back through the shorter of the tunnels and left the track at Lyncombe Vale Road and worked our way back to Bath Narrow Boats. We thoroughly enjoyed our ride and couldn't have asked for better weather!!! Beautiful. Thank you all for your input. We're already talking about the 'next time' and how we will spend the day and head to Bradford on Avon..... :)
That sounds great, and I am glad it worked. So do Bath Narrow Boats have few bikes? Lyncombe Vale is a good place to get onto the cyclepath, but the landowners/locals didn't like the idea. It can get a bit muddy.
Bath Narrow Boats had a good 20 odd bikes and were very accommodating.
Totally understand your comment re Lyncombe Vale - lack of signage (which explains why we went through the tunnel twice) and an awkward metal stile meant the bike had to be lifted 1 1/2 foot over and yes, lots of mud!