We are in Playa Hermosa with 4WD and wish to see Rio Celeste. Most info seems tp talk of visiting from the Arenal area. Can we get into the park from the North? What kind of drive is involved? How long is the hike to the waterfall? Strenuous? We were already in Arenal and would rather not drive all the way back. We would do the visit independently. Thank you for your help.