There is a difference between issuing executive orders to carry out one’s constitutional authority, and assuming extra-constitutional powers. A common position among libertarians (and many conservatives, such as myself) is the principle of non-delegation. Since the constitution does not grant Congress the power to delegate its lawmaking authority to the executive branch, “regulations” can’t be made by the executive. By extension, the entire regulatory apparatus that sprang up during the New Deal is unconstitutional and unlawful.
Going back on the gold standard is a different matter. It’s as simple as saying that the gold clause of the constitution will be honored, and the gold window is open at the US Treasury. It isn’t making new law, since no law ever closed the gold window. It was arbitrarily closed by Nixon. If you think this is a stupid idea, then amend the constitution to strike the gold clause instead of ignoring the parts you don’t like.