Err I don’t think the way of the roses would be ok if they want flat!
My wife and I did our first tour a couple of years ago and did the Kennet and Avon Canal route that Sustrans have made. Start in Bristol, easy to get to, there are longish flat parts but it does go off the canal a fair bit in the middle where there isn’t a towpath and along country lanes. Loads and loads of pubs and tea rooms, amazing scenery. Finish in Reading so easy to travel home.
We stayed the first night in a B and B near the Caen Hill locks and watched the sun go down while sitting near them. I can recommend the B and B but I can’t recommend the place we stayed on the 2nd night.
We did 40 ish mile days and absolutely loved it. Not so easy that you would find it done in a morning but if you take it easy and stop loads to have a beer or sit and admire the views it’s a perfect length.