You’ll need to make it to Georgetown, Guyana first. Guyana is a former British colony (Everyone speaks English! and drives on the right.) made up of the descendants of African and Indian indentured servants. People are friendly, food is fantastic and fresh. There are some bad areas but lots of good hosts and guides to navigate the city. Spend a few days enjoying the city and then book a flight from Georgetown to Kaiteur.
There are a few local charters and you should call ahead to confirm the prices, dates, group size. Aim for a large group as if many cancel the flight can be bumped to another day. Also check the weather ahead of time. Prices are around $200 Round Trip. After shopping around I decided to choose Roraima Airways Tour as they are reputable and have been operating for many years.