This is a great little traveller retreat in a beautiful setting by the river. It is located very near Semuc Champey (falls and swimming pools) and there are caves to explore for the adventurous.
Accommodation is in simple wooden huts on stilts with hammocks, the grounds are very lush and green. There is a great little restaurant near the river complete with swinging bar stools.
If you're there on the right night, expect a party atmosphere, this is a great place to meet other intrepid travellers. It's not an easy place to get to so it tends to attract only people who can be bothered to make the effort!
The facilities are what you'd call eco- long drop toilets (v.clean) simple showers. We didn't want to leave.
Get here from Coban (which itself is five hrs from Guat.city). It takes about two hours in a collectivo to get to Lanquin from Coban. Or try the great tour from dona victoria hostel in coban of semuc champey/ caves and they'll drop you off at El retiro on request! El retiro arrange a direct shuttle to Antigua (this took us 7 hours and was well worth the $15-20) and I think maybe they offer shuttles to Tikal.
www.retiro-guatemala.com/