The top of the pots will get you there, with a bit of imagination. Basically, it's all really close together; you'll find the way to the sump soon enough with a copy of the description with you - and without, you'll find lots of other bits too.
Please note that, while I've no idea how it responds to rainfall (ask someone in the RRCPC?); I'm pretty sure that the Cascades below the second pitch would be very sporting in high water. The Wet Crawl before the sump also has a bad feeling if the water was rising. Take care and play nice...