Welcome to the RTA Forum!

I'm sorry, but you really just aren't at a point where we can provide much help.

With 2-2.5 weeks you could go nearly anywhere in the US - it takes about a week to drive from coast to coast - and from New Jersey pretty much everything is "west."

"The National Parks" also says very little, as there are 58 national parks, and 74 national monuments located in nearly every state in the country. There are certainly plenty of them that are still very active in the winter.

You really just need to spend some time with a map, looking around at books and websites like this one, so you can get an idea of what sounds like fun to you. Of course, also think about how you want to do this trip - in terms of how much time you want to spend on the road vs time exploring.

Once you're at a point where you know what you want, we'll be glad to help you put things together, but right now and "ideas" we could offer would just be shots in the dark.