Selling the gold in Ft. Knox is, to me, a non-starter. Even if we no longer have a gold-backed currency, that's part of the backbone of our economy. Besides, as someone pointed out in reference to this in the Washington Post, dumping that much gold on the market at once would depress prices anyway. Selling it little by little to keep the prices up might help in the long run, but not much for right now.
Privatizing the interstate highway system is a terrible idea. We're free to move from state to state, but have to pay to do it? Sort of a contradiction in terms, to me. Private interests shouldn't be able to decide who gets to wander around the country and who doesn't.
Selling off some government buildings might be a good idea, especially as telework takes hold. Of course, some of them are historic (like the Archives building, for instance) and shouldn't be sold; also, some of their property is leased anyway (like the new-ish Patent Office complex in Alexandria, VA). Selling off government lands such as national parks, however, is a terrible idea. Those weren't established for us to sell, but for our children and their children to enjoy.
Raising taxes, however, should be a no-brainer. Especially with the weird, lopsided system we have, whereby people who rake in the most money pay the least tax. We pay the least in taxes of anyone but, I think, Australia, among the developed countries. It's no wonder that our infrastructure is falling apart. We need higher taxes for, probably, the top 70% or so of the population (I have no numbers on this - it's just a guess), and more steeply the more money people make. Americans have become so selfish that we can't stand to pay for a road we, ourselves, don't drive on, or a park we, ourselves, have never been to, and that's not what this country is for. We all need to look out for the whole country, rather than our own narrow interests, and to do so, we need to pay higher taxes.