After WWII, the U.S. had an even larger debt, as a percentage of its economy. Still, we managed to pay it off in 10 years, and rebuild Europe at the same time, without collapsing the dollar.
We can do that again if the government pursues the same pro-growth policies.
We had a 26% inflation rate in 1946, the highest in modern times. We were on the Bretton Woods foreign exchange system in which the value of the dollar was guaranteed (exchangeable in gold at a fixed price), so collapsing the dollar was very difficult. But it finally did collapse in the early 1970's and we paid for it with high inflation and a stagnant economy in that decade.
You are right about pro growth policy. There is no other policy that has anywhere near the leverage when it comes to keeping inflation in check, a currency stable, and increasing the standard of living. (A balanced budget, something Hoover and Carter promoted, pales in comparison.)