The AI pilot will go straight to the main objectives. Not to optional objetives.
The AI pilot will get very close to the objective, which is only detrimental. Two Reasons: First, the AI pilot will not attack surface targets (e.g. radiators). In fact, I have seen the Railjack (not sure if gunner or pilot fault) attack invulnerable turrets. And second, since the pilot gets close to the objetives, the Railjack will be attacked by Ramsleds. I usually responded by making the 5 points gunner who didn't shot down the Ramleds be defender when boarded, and together with the engineer they'd fix the p