It's always amazing to me that cabs are as quiet as they are given the amount of noise immediately outside the cab and hey small amount of insulating material used.
I've gone through a couple vehicles of mine in the past and deadened them the best I could. It's an interesting project. Some things work... Some don't.
I think there are three main types of materials to work with. Deadeners, diffusers, and resonance alteration materials. Ideally you use all three but it gets expensive and time consuming.
Personally I've found mass loaded vinyl to be the best at deadening wind noise. You can buy it online or at home Depot in large sheets. It's hard to use in vertical applications though given its weight.
Dynamat and other adhesive butyl rubber materails are great for reducing buzzing or that tin sound in cars/doors but dont much for road noise.
Tire noise is tricky. Hard to kill. Different tires are the biggest and best way to reduce this. Michelin defender LTX are wonderful for ride and noise but the off road looks aren't there. I've lined nearly an entire cab floor with MLV, diffuser mat, and dynamat with little effect on tire hum. I think it's largely because the vibration can travel through so much metal and come out in a lot of places.
If you find a spot that is problematic, give the MLV a try. Especially if you can slide it under carpet or something. It's heavy and hard to work with (especially in vertical applications), but it works.