Best European places to cycle?

[KnitMeAUnicorn]

I know the Netherlands is the obvious cliche but I'm sure there are other places just as good. We'd like:
• mainly flattish but some degree of undulation would be fine
• either extremely rural, one car passing every 10 hours kind of thing, or else totally dedicated cycle paths – not prepared to run the gauntlet of traffic at all
• suitable for fit kids aged 12, 10 and 7.
• half-thinking of combining it with a bit of a barge holiday and doing a lot on canal towpaths, if that helps? HELP!

We had a lovely summer cycling holiday in Brittany a few years ago - mostly flat on paths near rivers, or on very quiet roads. Some inclines but nothing too awful! The hills were worth it for the views though. Same age kids as yours. The weather was good but not too hot.

My friends organised it so can't remember exactly where it was - in mid Brittany, inland and very rural. We hired bikes and accommodation together from the company (either camping or a Gite). Hopefully you can find it online if that sounds of interest!

Sounds lovely, Sonny, hadn't thought of Brittany! Will investigate ...

Brittany has great cycle routes specifically Loire Atlantic region
m.cycling-loire.com/lav/other-cycle-resources/cycle-routes/velocean

France generally is great for cycling

Just back from the Mosel Valley in Germany - flat well-maintained dedicated cycle paths up and down both sides of the river - no hills as riverside, idyllic scenery, castles, vineyards, wine. And more wine,

Currently in Burgundy - south of Dijon
There are some great cycle routes here.

We've only explored a small area, there is a large network. Check online
The voie verte and voie bleu (on rover/canal)

Copenhagen - gorgeous, friendly city and fab to cycle.

We cycled through th Loire valley. Great food, chateaux, good value bike friendly hotels, v flat and cycle paths. Lovely.

Loire valley. Flat, safe cycling, great food, lovely reasonable bike friendly hotels. Lots of families cycling and touring. Did I mention the food?

How about one of the Eurovelo routes?

There's one along the Loire, one along the Rhine. Plenty of others.

So god I told you about it twice...

The Donauradweg - cycle route along the Danube. We did the bit from Passau to Vienna, renting bikes in Passau and leaving them on the outskirts of Vienna. Very flat. Some shortcuts possible by boat/train to cut down the mileage. There are plenty of organised tours but we planned our own so I could make each day the length I wanted, and so I knew exactly where we would be staying. Beware of some of these tours where the hotel is 'in the vicinity' of somewhere but actually takes you a fair distance away from the river (and probably uphill). Kids were 14 and 11. Feel free to pm me if interested.

I have also considered the trip round Lake Constance/Konstanz too.

Denmark- like the Netherlands but far less traffic. No canals, but if you head for somewhere like south Funen there will be a few boats.

Lots of history, and the option to get trains to places too.