,if you know the forces acting on the ends of the rubber band, then using a force directly at the locations where pins are connected onto the two bodies will be okay. If the heights of the pin is considerable according to your thinking (I would had compared the height of the pin with the size of the bodies), then using a remote force is going to be true. I would try using the force instead of remote force as much as possible since using remote force increases the constraint equations within the analysis, making it take longer time to solve than if only force is being used.
But keep in mind that if you are using static structural module, you need to apply boundary conditions somewhere within the model to avoid rigid body motion. Thats up to your judgement where to apply these boundary conditions.
You can calculate the force acting on the rubber band if you know how much the band has stretched in reality when attached between these two bodies, then refer to the stress-strain or force-displacement graph, find the force from the graph where the displacement is half of what you have noted in reality.