Splodge, I looked it up.
Pont-De-Seraing. Gare de Seraing is an abandoned railway station (or freight only?) since it is not serviced by the SNCB/NMBS.
This means the walk is a bit longer, and you will have to cross the river Meuse.
For planning:
https://www.b-europe.com/TravelThere are direct trains from Oostende, Gent, Brussels to Liège-Guillemins. From Antwerp you have to switch in Brussels or Leuven.
In Liege you switch to the local train to Seraing.
I have myself never bothered to visit the RLD's in Liege and Seraing, so cannot comment on it.
You might check out youppie dot net for up to date info - it is in french though.
For negotiations it is probably practical if you know some basic RLD-french, like numbers, and 'combien pour la pipe et l'amour'?
Don't know if it is worth the trip, and Seraing has an industrial look - might be interesting if you are into photography of abandonded steel mills and stuff.