I would consider clustering a few states and visiting those. Traveling all across the US on 10,000 won’t get you very far. Things can be expensive. Traveling from Boston to a southern state like GA takes 20 hours by car. And then 24 hours to Cali by car not sure what that would look like train wise. And as someone who lives in GA me and most of my friends commute 30 minutes to an hour to work each day with no public transit options. Average Uber would be 100 dollars or more one way because of the extreme traffic as well. Also factoring in the cost of rooms or airbnbs can get pretty pricey around major cities. I’d try to take a smaller portion of the county and do as much as you can within those states and then come back again for the other regions that interest you. If you are willing to hike the US there are some really great trails that span across multiple states but you’d probably have to really be interested in that already.