The access to Beulach Ban Falls is just before you leave the park (travelling north-east towards Big Intervale and Cape North). A 2 km-long single-lane dirt road leads to a small parking lot. Signs advise that you are using the road at your own risk.
There's a small parking lot at the end of the road. Despite the warnings, there were four cars (including our own) there. A short walk along a good path leads to the falls.