I've been thinking about this for a minute and it seems pretty hard to implement alongside linear roads.
If all of them are an underpass, then I guess that can be done, but then you will have entries and exits at each node, which will need to be avoided even by normal pedestrians.
And that also causes visibility problems between 2 skateboarders and they don't have the option to stop, mid pump/jump. So, you absolutely need an open track.

And in case of an open track, you can't go with a slope in just 2 directions, because then the other 2 will end up with a steep fall. So you will need a slope in all directions from the edges of the track and that would require a lot of area.

Now, since road bicyclists work well with normal road rules, having a pump track at the sides of the road, will make it harder for everyone, due to cycles requiring to pass them when going into whatever building is beside it.
So, I guess the divider can be replaced with a track, which might end up being as wide as a whole (or multiple) lane depending upon the required depth of the track.
If the depth is like 1 foot or so, then I would consider the width of a divider (about 1/3 a lane) to be good enough.

Another way, in case the pump track can be less than even 1 foot in depth, to be useful , is if skateboarders can use it to pump with sideways movement, while going forward on the road. Then perhaps there can be plane road junctions at nodes, which would be pretty easily visible.