Did the Sid and Marty Croft show, Land of the Lost, take place inside a hollow Earth? I seem to remember day and night in the show which often would be impossible in the hollow world mythos. I wondered if it was ever established where exactly the Land was (I suppose that would've made it 'Land of the Found').
No, it was an alternate universe story, not Hollow Earth.
The Marshalls are brought to the mysterious world by means of a dimensional portal, a device used frequently throughout the series and a major part of its internal mythology. This portal opens when they are swept down a gigantic 1,000 foot waterfall. We later learn in what should have been the series finale (titled "Circle", which explains the time paradox) that this portal is actually opened by Rick Marshall himself, while in Enik's cave, as a way for the current Marshalls to return to earth, resolving the paradox and allowing Enik to also return to his time.
I remember another Hollow Earth story, DC Comic's Warlord, which took place in Skartaris. One feature of the story was a moon that orbited the inner sun, resulting in brief periods of darkness at certain times and places.