The "Dismount and join a new rail" system is the easiest to set up and for people to use. Just make sure there is sufficient land around each stop point to allow the player to dismantle their cart from their old track without them loosing it over the side.

Is anyone having a lag a couple of meters away from new spawn station when using rails? I wanted to try it yesterday and both by foot and by cart there was an uber lag for me near new spawn station despite riding perfectly fine all the way from old spawn till that point

same here. the lags seems to be mostly 1-2 chunks at z ~= -870. A bit northwest of the skyrail station someone started a sheepfarm with ~100 sheeps. Maybe that causes it when the sheep chunks are loaded/unloaded. Maybe. It's ~110 blocks away so the distance would fit.
Did set /warp addyreport there if a mod wants to check that out