Golden Road is a character within a story, not a player with access to the corebook. While she theoretically has access to the full breadth of Solar powers, in practice what she has access to is the supernatural manifestations of the skills she already possesses. She is a horseback magistrate who has spent her life mastering the martial arts, so her Exaltation took her skills and magnified them to superhuman levels. Most of the time, this does not feel to her as deliberately "activating a power"; what is mechanized in the Exalted RPG as an Excellency is intuitive to her, as are certain Charms. She is capable of endearing herself to an entire village to the point of children sharing family secrets in a scant few days, as well as to intuit the nature of the Steel-Fanged Adder's lost relics and what they mean for the school's history and Nashai's goals from a quick look at a weapon rack; these are understated examples of Solar prowess. Her display of martial arts is more overt because she has to consciously burn through her inner power to compensate for her crippling injuries, but this is more akin to someone "getting in the zone" or focusing all their attention on a task at hand than it is to "turning on her magic." It's just that when Road starts giving something her all, she spontaneously manifests the mantle of divinity by which the Chosen are recognized.
If Golden Road wanted to fix her legs, she couldn't simply spend XP learning the right powers. She would have to actively seek out training - perhaps spending months or years studying under a doctor, or seeking out sorcerous teachings, or apprenticing to a craftsman to make her own prosthetic legs. And she would have to actually be good at it - Solars are not immune to the simple human condition of just not vibing right with certain skillsets. Some people remain bad at maths no matter how long they spend learning them, and some Solars will never get the hang of wood-carving no matter how long they try. Any of these developments would be an advanture in its own right; there is no reason to assume that learning freaking Sorcery would be any easier or quicker than venturing into a land known to held an Artifact that can cure her condition. Nor are Sorcerers who can be convinced to perform a working that would regrow her legs plentiful or easily available - and if one is found, they might not be trustworthy, or the cost they ask for might be too high.
It's a wide harsh world out there, and a single Solar has limits. Being an Eclipse Caste, Golden Road isn't even guaranteed the degree of invincibility that is often presumed by Exalted fans when talking about Solars in battle - there are plenty of things out there who can challenge her or threaten her life. If the eight students of the Adder had known she was a supernatural being and coordinated accordingly, Road would have had a harder time dealing with them. They underestimated her, and paid the price.
