Having been in the car business years ago, more than likely you're gonna be a little bit more "upside down" than you think. Generally, you can trade once from a short term purchase and be able to absorb a lot of the negative equity in the new deal. After that, it's virtually impossible to trade out without a lot of cash. There is always a way to get it to the payment you want, this time it took a 7 year loan.
Since you did an 84 month loan, it will be well into the 3rd or 4th year before you have the potential to be at a break even point. If you can constantly afford to keep putting down a big chunk of money every 1-3 years whenever there is a body style change from one of the big 3, the the banks and the dealers will appreciate it. If you like the Ram, but not the size of the tank, just get an additional tank.
The new Rams will be out in 12-18 months....what then?