Fortunately Harry Harrison wrote the 1967 novel The Technicolor Time Machine as a very broad comedy, and it's clear from the start that the sense of general preposterousness is fully deliberate. Harrison's got a long career writing comic SF; he's probably best known for the Stainless Steel Rat books, of which I've read the first three. They're pretty good examples of the "ludicrously competent interstellar hero thwarts the bad guys and saves the day" genre. He also wrote the book the movie Soylent Green is very, very loosely derived from.
The Technicolor Time Machine is amusing, although much of its humor is a satire of the Hollywood of the 1960s, already somewhat out of date and getting more so all the time. (In fact, I'd wager that with the accelerating evolution of entertainment media, the next 15 years might well alter the business side of how movies are made more than the past 40 years have. Kids these days won't understand the older generation's satires of Ye Olde Hollywoode.) And characters like L. M. Greenspan and Ruf Hawk are comedy tropes you've surely seen a dozen times before.
So what about the science fiction side of things? The book's got some neat moments, but it doesn't really do anything new or mind-blowing with the time travel trope. Yes, I remember it was published in 1967 and Back to the Future was still nearly two decades away, but written science fiction has always been more imaginative and daring than its celluloid cousin, and Robert A. Heinlein's rather more mind-blowing short story "All You Zombies" predates this book by eight years. To sum up: use of time travel trope, competent but not extraordinary.
And what's with this piece of dialogue toward the end of the book?
Barney clutched the paper. "Let me get this straight. Are you telling me that I can make the film after the deadline, then return to a time before the deadline to deliver the film?""I am.""It sounds nuts.""But Barney's been zipping back and forth in a time machine for the WHOLE DAMN BOOK!" said the reader.
That last line was my addition.