Ignoring the comparative levels of freedom in the respective countries, wouldn't it seem to be a safer bet to seek asylum in Russia than Venezuela? Russia seems far less politically volatile and more likely to resist US pressure over a 50 year time span.
I doubt the government would let him keep publishing his works. While it is an ok solution he might want to go to the country that will let him to run the course of his disclosures.
My understanding is that Snowden has already given everything to a bunch of journalists, encrypted, who can access the data even if something happens to him.