If you like the vast and endles nature you have to go down to the Gran Sabana. It is in the state of Edo. Bolivar.
On the boarder to Brazil. Small town called St. Elena de Uairen... you can do alot of trips from there. Visit Tepuis, Canaima, Angel Falls, do some gold mining for fun. Take the dead end road to Icabaru/Pauji.... awsome offroad experience, nice scenery. In Pauji or better @ Cantarana you can go for day trips to the Abismo ( dont miss it ), awsome view over endless jungle south to the brasil boarder.
I was born there. Was there last time in 2010, going back hopefully next year with my bike
I would skip Caracas, or any major city.... the criminal rate is extremelly high. I think Caracas is even number 1 on the List of the most dangerous cities worldwide.
Dont mind the GN ( Guardia Nacional ), just some wannabies. Be carefull with the black market, dont try to change big amounts of dollars.
You will need the yellow feaver vacc. stamp with you, or they wont let you in the country. Only if you come by land, they never asked @ the airport.
Most of all... have fun