I have a 2012 Silverado with a 3 in lift, are the 4x4 trails big enough for a full size truck? Are the width of the trails ok for a big truck and height of the truck? Plus how strict is the noise law?

There are a few places that may be a little tight for a full size truck. The noise regulations are clearly spelled out on the website. https://www.fs.usda.gov/recarea/nfsnc/recreation/ohv/recarea/?recid=49004&actid=93

Yes they are big enough for a full size truck and no noise laws on the trails but a state trooper might try and bug you on the way there