Yes, certainly. Many things can go differently. For one the US President, Obama, might go there on TV and tell: "My fellow Americans. Starting tomorrow we are raising taxes by 10-25%. We cut social security. We cut military. We cut across the board. Why? Because the Chinese demand their money!"
Possible? Of course! Probable? Your call.
Inflating the monetary base is actually doing the same, but without the need to raise taxes ex explicite. Everything gets more expensive year to year: tuition, insurance, services, etc. That's your hidden tax - inflation. We are paying off the Chinese by returning them money that's less valuable that the money we borrowed from them.
Some things, like 600% debt to GDP ratio that currently the US has are just facts of life. Can I imagine reality without them? Sure! The media is full of them from CNBC to Bloomberg News. Why you insist on me providing you scenarios? Ask them if they can imagine bubble in Treasuries! They certainly couldn't see one in housing or the .com one even though they both were straight in their faces. They laughed off anyone talking about bubbles then. The same now they lough into faces of Peter Schiff, Marc Faber, Jim Rogers, Kyle Bass, and others when they talk about bubble in the US Treasuries. In other words, you are asking wrong person to do the reality check. I'm the reality check to the mainstream camp blind to the obvious. 600% debt to gdp.
Can FED raise the interest rates to stop all the bubbles in their tracks? Sure they can! They need to be cautious though. Because at interest rates at 7%, the US Government will be spending over 50% of the annual budget just to pay interest on the debt we have. Can we imagine the FED going to raise the rates to 20% as Volcker did in the early 1980s? Sure, but then well over 100% of the state income from taxes would need to be paid on the interest alone! This is how much we owe. Can I imagine reality where this is not true? Sure, but why would I ever do that? Why to imagine world where mistakes aren't happening when they are right in our faces?
I'm not saying we don't have options. I'm just saying that taking into the account the dirty politics, we can't have the President have speech like that, can we?
Another solution: war. In the state of war we don't repay. That's the rule ages old.
So, yes there are plenty of scenarios: from bankruptcy, theory hyperinflation, ending on WW3.
There is no positive outcome from debt to GDP ratio at 600%. Sorry.
One could argue that we will just have "lost decades" as Japanese did. That the process will take forever and we will slowly decline and the rest of the world will follow suite. Might be that it will take 30 years. The thing is that looking at Russia, China, ISIS, I don't think they will just let us decline.