I spent three days at dOCUMENTA (13) in Kassel. I have to say I had enough, but should you want to see from A-Z you better stay 4 days.
I recommend first going to the Frederician (the main museum). There you have a taste for the exhibition. A mix of art/science/politics/minorities. I have to say that theme is a little bit of the same. The axis Kassel/Kabul/Cairo/Banff is also a “and?”.
Near the main museum, in a building there is a beautiful work by Walid Raad.
Go second to the the old train station. There are several good works. The one you cannot miss is the iPod walk work by Janet Cardiff. It is really unbelievable. Near the station there is a place with several beautiful works by Harris Epaminonda and Daniel Gustav-Cramer.
Third go the Neue Gallery, the best work there is a work by Sanja Ivekovic. Near Neue Gallery in a WWII bunker there is an interesting video by Allora & Calzadilla.
The park is where dOCUMENTA (13) became boring. One has to walk a lot to see everything and it takes time. Rent a bike and enjoy the park. The park’s map is a mess and you loose a lot of time looking for the works. Don’t miss the other work by Janet Cardiff, Jimmie Durham, Anna Maiolino, Atila Csorgo and Time Bank.
Overall dOCUMENTA (13) talks a lot about right/wrong and themes that in my point of view have been exhausted lately in the art world.
Summarizing, Latin American art is more pleasant than the ones of the northern hemisphere.