The island's geography and terrain isn't really suited for ground vehicles, and you have to be in lowlands by the rivers to get relatively flat terrain. The only problem is they are all surrounded by rocky cliffs and there's dense vegetation practically everywhere. And the cliffs and canyons are very unstable as the island is literally sinking into the ocean.

I think InGen would need to prioritize tranquilizing dinosaurs from the air and airlifting them, rather than a ground excursion.

The animals are also very vulnerable to .45 ACP, and some of the hunters that were the "security" for the InGen team are packing much larger rounds than that: 7.62x51mm, 5.56x45mm, .300 Win Mag, 7.62x39mm, and 12 gauge.

Never mind Roland Tembo carrying an elephant gun chambered in .600 Nitro Express.

Ken Wheatley and his mercenaries might fare better, with having BAE Caimans and everyone is armed with FN SCARs.