Fear and Loathing in Gonzovision AKA Fear and Loathing on the Road to Hollywood, is a 1978 film produced by BBC Omnibus and directed by Nigel Finch.
Here’s how Documentary Heaven described the film:
A fascinating, 30 year old BBC documentary on the Good Doctor and Ralph Steadman, five years after Nixon’s resignation, and on a road trip to Hollywood (to work on what would become Where the Buffalo Roam).
Includes an interesting scene of John Dean chatting with Hunter about his Watergate testimony (at about 32 minutes), the birth of the “Re-Elect Nixon Campaign” (with a Bill Murray cameo), and a remarkably eerie scene with Hunter and Ralph planning Hunter’s final monument and his ashes being shot into the air, long before the actual fact.