I've been reading Peregrinacao by Fernao Mendes Pinto (in English, as it was written in the 1500s); a weird sort of Portuguese Marco Polo. As my language skills improve, Aquilino Ribeiro is on my list.
Ibn Battuta looks pretty cool; thanks for mentioning.
The most insane and extreme adventure I have ever read is Cabeza de Vaca's Naufragios. Marooned in Florida with a few companions and one slave, and then himself enslaved by native americans (he famously quipped that his poor slave became a slave's slave), they ended up being the first europeans known to walk the US coast to coast, as a chaman with his entourage. A very resourceful man. His observations of the many american tribes he came across were a first, he had an anthropologist's outlook. A short but intense book.
Something that plays a role is how the book looks like, there are some copies closer to our days that kind of preserve the form, but update the orthography, while others are just as they were written originally.
So one gets to decipher stuff like effe => esse.