To be honest, you will be fine on trail 1 with a stock JKU. My 07 JKU did fine out of the box bone stock with 35s. They have a website with all the info on all 3 trails. To do the other 2 trails, you would def need some mods.
When I die, bury me in my Jeep. Its never been in a hole that it couldn't get out of!