Dynamat is great if you're wanting acoustic damping for high output stereos. Minimizes panel resonence & rattling. Can run you upwards of $2-400 to do a whole interior tho.
If you're just wanting to put in some decent insulation to damp the road noise & keep it warmer/cooler inside there are MUCH cheaper alternatives.

They sell the rolls of 1/2 thick felt/foam sheet with aluminum coating on one side on the JC Whitney bebsite. It's like $18 a roll & should take maybe 2 rolls to do your whole cab. I used it in a car I did a total restoration on, headliner, doors, rear qtrs & floor. Made a HUGE difference in sound & kept the temps manageable.
Just get some good spray adhesive like 3M-99 or better, cut, fit, stick, & you're done.