I saw this film on a drive in double bill with THE LAND THAT TIME FORGOT - and had read the books when I was 11 years old (Ace Paperbacks). LAND has hand puppet dinosaurs that don't move and look silly, PEOPLE has men in rubber suits as dinosaurs that look silly. Both films change the Burroughs stories (probably for budget reasons), but PEOPLE does something interesting - it combines the 2nd and 3rd book in Burroughs' series, using Act 1 of PEOPLE and Act 2&3 of OUT OF TIME'S ABYSS. The Weiros from ABYSS have been changed into Nagaas - a volcano cult dressed in Japanese Armor. (The Weiros were humanoids evolved from Pterodactyls - hard to do on a $1.98 budget.) This way they could take the old prisoner from ABYSS and turn him into Doug McClure's character.
PEOPLE is much better than LAND for a couple of reasons. LAND not only had crappy FX, it looked like it was shot on an indoor stage! So even when there isn't some bad process shot of a hand puppet T-Rex growling, the movie looks fake. PEOPLE was shot on location in Spain, and has some nice big panoramic shots - one amazing shot of the team crossing the crest of a mountain looks like something out of LAWRENCE OF ARABIA. The other reason why PEOPLE is better - cavegirls! If you read the books (with Frazetta covers) there were always half-naked cavegirls. As an 11 year-old boy, reading these was like discovering your Uncle's Playboy collection. Half naked girls! LAND has no cavegirls at all, PEOPLE has the Ajor character from the novel in a laced leather outfit that fits the drive in AIP scenario to a T.
I love the books, and would love to do a modern adaptation (with today's FX).