If you are a group of 2 or more and are about to embark on this journey. Pay the park ranger to trek the mountain on your own.
They wouldnt let me go as I was solo but there reason for not letting me go was that very reason.
The ranger was a d!ckhead because he would have got a decent days pay if he had of let me go alone, but he did say anymore than 1 and its possible.
So dont believe all the bullsh!t you read in lonely planet and websites. You can trek this place without a guide.
If you are crossing into Venezuela from Brazil, it is best that you withdraw quite a handful of Brazilian Reais first. Just before the border-crossing, some guys would board the bus and change the Reais into Venezuelan Bolivares. To be honest, the rates here are quite reasonable and you definitely need some Venezuelan Bolivares when you arrive in Santa Elena, which is a very small town indeed.