As #2 mentioned, a few minutes walk from Hacienda Merida is Monkies Island (yes, they figured out it should have been Monkey's). I stayed there three years ago during the weekend of Semana Santa and have great memories of the place. It is very rustic but what made it special was the hospitality of the family. There was no tv, just a boombox but the men are expert checkers players and were always up for a game. The preteen daughters were sweethearts and eager to talk with tourists who had some knowledge of Spanish- they'd hang out with me in a hammock and ask all sorts of questions about what my life was like back home. They were eager to learn English, as was their Dad, and they would join in when I and an Italian tourist sat around studying Spanish...a really fun language exchange.
I visited the waterfall (which I learned from another thread has been ruined by a landslide) and went to the little beach for swims (the girls always tagged along). The oldest son leads hikes up Maderas volcano (I wasn't up for that but a German tourist told me it was great, with spectacular views).
I had a private cabin with a double bed with comfy mattress and impeccably clean bedding (the Mom is often hunched over the wash basin, all done by hand!) and the bathroom is a few metres away, shared. They also have dorms with four beds.The place is very rustic but well kept and very cheap. I think I paid approx $5 a night and the food, prepared to order was also very inexpensive.
It's a great place to chill out and has an excellent vibe. I highly recommend it for easy-going people who can handle rustic.
I still occaisonally email one of the sons and though he and his Dad were building more cabins and making other improvements to the property, he always writes that Monkies Island doesn't change.