Closed Saturday and Sunday
Just in case it has not been stated before, Rio Sereno Aduana on the Costa Rica crossing is closed on Saturday and Sunday for vehicles. Foot traffic is still OK.
Not sure about Panama Aduana, but if Costa Rica side is closed you can bet Panama is too.
You may want to check on this before you head that way, things change especially on a major holiday; and weekends are major holidays to most of the locals.