This is as easy as it gets for cross skates.
This is an isthmus that goes 5 km into the Bieler lake.
No major turns, wide path, straight line, perfectly press hard sand without big pebbles (at least in the first 3 km, virtually no motorised traffic, decent views, car park at the start..
I would say the first 3km can be done comfortably with smaller 15 inch wheels and for the daring one even solid rollerski wheels.
In the farthest section where the turn starts there are some larger pebbles which would make going there with 15 inch wheels interesting but doable.
Average speed was 15.7km without going at full speed so as good as it gets.
I am investigating the paths described in Schweizmobil that are "wheelchair accessible"
to see which ones are gravel and which ones are asphalt. SchweizMobil Obstacle Free
(p.s. the one in Estavayer le Lac starts as asphalt, I started only a brief section).