Rail trail going from town to town at a ~1% gradient. It's called the Ghost Town Trail because while it does go through some existing towns, it also passes by what remains of various "ghost towns" - towns that sprung up to produce coal but eventually were abandoned once mined out.

https://www.indianacountyparks.org/trails/ghosttown_trail.aspx

Het Schipbeekpad (80k/330d+)

The route runs from Germany a impressive tour through the beautiful Twente and Salland or in the opposite direction from the hanseatic city of Deventer to Germany. With this route you run as much as possible along the Schipbeek (a canal/river). From the late Middle Ages, this river was channeled for the transport of cheese and butter to Germany and loam and wood to the Netherlands.

The Dutch poet Paul Gellings wrote a poem about the 'Schipbeek':

Entre Lesse et Lomme voert je 78 km lang door de Centrale Ardennen in stiltegebied door afwisselend lichtgroen gebladerte van loofwoud en de donkergroene naalden van dennenbossen. Af en toe wordt er nog een streepje kabbelend en ruisend blauw aan toegevoegd, als je een van de vele Ardense beken oversteekt die van de hoogplateaus afwateren door de bossen of tijdens de absoluut prachtige passages langs de twee grote Ardense rivieren die deze wandelroute als thema heeft: de Lesse en de Lomme.

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