Having imported a Land Rover to the US from the UK, I can tell you exactly what the DOT/US Customs will be looking for:
1. There is a thing called the DOT "Good List". If a vehicle is on the list, importing is somewhat easy. You need to go through a registered importer.
https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/elig120115_v2.pdf
B. If your vehicle is not on the Good List (I did not see a Hilux on the list), the vehicle MUST be more than 25 years old. That's 25 years from the date the vehicle rolled down the assembly line. You must be able to prove that date. Easiest way to do that is 25 years after the date of first registration.
III. Those steps get you through the DOT. Now you have to get through customs, where you will need to pay duty/taxes. Here is where you will run into the chicken tax, and there is no getting around it. If the vehicle is considered a "car", the duty is 2.5%. If the vehicle is considered a truck, the duty is 25%. The crazy thing is it's the customs officer who decides. In the case of a Defender, there were two things that "drove" the decision. The first was "was the rear compartment designed for passengers or cargo? In my case, carpet, seats, and the term "station wagon" on the original (25 year old) bill of sale describing the model helped the officer decide it was a car. The second thing was the port of entry. I came in through Baltimore, and my description, plus other customs decisions on the subject sealed the deal. The horror story I heard, however, is those that chose Port Hueneme in California had a customs crew that ALWAYS determined truck. You could challenge that decision, but only after paying first and trying to get a refund. In the land of Land Rovers, I have yet to hear of anyone who successfully received a refund. If you're bringing in a Hilux, plan on that 25%.
Now, that's the import process. EPA does not come in to play (vehicle over 25 years old. However, your state may have different requirements. Where I live, described recently as the most free state in the Nation, there were no problems. If you are in California, however, you are never getting past CARB.
This is getting long, so I'll stop there. If you need more info, PM me.