Bruce Dern as you guide??

When you say Hopper, I think you mean Peter Fonda, who was the lead character. But yes, I almost thought Dern was intentionally trying to mess with Fonda's mind, like when he was trapping him in the corner hallway, then shoving the chair into his face, etc.

Also, when Fonda first went outside with the orange, Dern raced out with him, then convinced him to go back inside to listen to some music. Anyone who has taken LSD will understand the need for a tripper to often get out of enclosed, indoor spaces and out into the natural world, which Dern was trying to discourage.

I wondered about the symbolism of the two black hooded riders on the horses following Fonda, and maybe that they were not just symbolic of death, but also one representing the spectre of Fonda's impending divorce from his wife and the other the control Dern had over him as his tripping guide.