This is what I did for the wife's jeep diesel rubicon. We live off road and she is a nurse so has to go to work in all weather conditions, plus we use it for going lots of places on and off road. I used to just take my main tool bag I keep in my main farm truck with us in the motorhome or other vehicles when we went somewhere, but I decided to buy a dedicated tool kit for her jeep.
I bought a 300pc kobalt set from Lowes, has 1/4", 3/8" and 1/2" drives, end wrenches (except a damned 9/16" wrench for some odd reason), bits as well for small fasteners. I then bought a tool bag to store it all in under the back seat.
