If she wanted the country to leave her alone to her own devices, should have given the princess the bicycle.
Bicycles, at least, can probably begin to be created by the local technology, so if it takes off, local craftsmen can pick up the slack.
Give the princess a radio, and let someone who sees it think about how insanely useful instantaneous, no-messenger long-distance communication can be for diplomacy ,commerce, communication, or war, and all sorts of official people will be hammering down her door requesting (initially) to have them.