If you are looking for realistic experiences playing On Demand Freerolls as compared to
real money ring games you will be, in general, sadly disappointed. Everyone enrolled in an On Demand Freeroll has no skin in the game except the time involved. Subsequently, participants may play "properly" while others will go all in on the first hand with junk like 10,4 (suited or unsuited, it is still junk). In fact, 10,4 will probably be gone after the first hand unless no one calls, which makes that move quite efficient time wise. What's the rationale? If I triple or quadruple up on the first orbit, now I will start playing sanely. Otherwise, I'm gone and I will go do something else until the next freeroll starts. So, the answer to your question, "How long does it take"? 3, 4, or 5 hours is you go all the way, less than a minute in other scenarios.