Any easy methods to max Insight?

You mean by leveling Herbalism? It's just as time consuming as Willpower.

True, but the OP's main concern was about Insight, a trait that can neither be over-boosted like Empathy, Willpower, Ambition and Diligence, nor does it compensate by having a high daily cap like Charm. You just need to buy a lot of seeds and get to training your Herbalism to max it but Insight will be a chore no matter what method you use unless you simply farm equips and use lenses on them since you're combining two activities into one.