Everyone is worried about discretionary spending, but that's less than 1/3 of the US's budget.
Being pegged to a commodity does not imbue money with any more magical power than if the dollar was pegged to Beanie Babies.
If a government wants to run amok with a money printing press, that will certainly create inflation. But steady, low inflation over time is a good thing as it keeps people from sitting on their money and shrinking the economy (which is what prolonged the Great Depression).
As for the dollar losing its reserve status - that might happen a lot sooner than you think. If the current administration has it's way and we eliminate trade deficits, there will not be many dollars in foreign hands with which to use as a reserve.