Pirius Black
Superstar
This is a death trap. First of all, the composition of the atmosphere has changed over time. The atmosphere was 35% oxygen, meaning while you could breathe the shyt just fine, this means a denser atmosphere. Meaning that any fire you start would rage out of control, an atmosphere that is 35% oxygen (65% more o2 than the modern era) would enable wet vegetation to burn, so cooking is off the table. Secondly, that high oxygen content in the atmosphere totally made giant insects and arthropods. Because the air was so much thicker, the early ancestors of dragonflies evolved to have wingspans that were sometimes as much as 2 or 3 feet wide. You had 3 ft fukking scorpions, big ass centipedes and 8 ft millipedes running around and shyt. Only the lower oxygen constrains insect sizes in our comfy, no dinosaur era. Hell, your fukking immune system would probably collapse if you even tried to eat the flora and fauna. You'd be going to an alien planet with only the barest slivers of knowledge that we gleamed from digging these b*stards up from the ground. Lastly, there would be the shyt you couldn't anticipate, unknown unknowns. Equipment breaking down, unknown species (Ancient Aliens?), the inability to predict the weather could dead you within 48 hours and y'all talking three weaks? shyt would be 1000 Ways to Die, Mesozoic edition.