Hmmm, I recall a Land Of the Lost show in which the first event was this:

There's this family and they are riding in a van thingy and go into this crack in the ground and end up in the land of the lost. They live in a hut and there is a T-rex. There's this hairy dude too, but I don't remember his name.

I'd say it was on TV from 1991-1994. I think the one I'm thinking about is a remake of the one you're obssesed with. 8-)

I really loved the show that I watched, it was clean and decent, the acting was good and so was the story.

Another episode that I recall involved the family thinking that the found their home. They can't find the Mom though. Then they find out it's just an illusion when bad things start happening to them. That was one of the coolest episodes.