To animate splines along surfaces, you have to go deep into Xpresso. There are ways to solve this mathematically and efficiently, but I haven't yet succeeded in this experiment. Instead, I found an alternative way that is a bit slower. The particles that generate the splines are shot at the geometry and pushed across the surface via collision detection and something like a rigid body simulation.
This has produced several simulations of different test objects. I believe that Xpresso can still be a very useful and powerful tool, even if Houdini and Xparticles are slowly making it obsolete. Since I feel Xpresso is not used much for particle simulations anymore, I am trying to find my own aesthetic in it.