Funnily enough, I'm also a unitarian. Unitarianism (the denomination) was pretty popular until the middle of the last century when it was mostly absorbed into Unitarian Universalism, and other denominations (eg. Jehovah's Witness) are still unitarian, so I wouldn't call it a "keystone".
Following the example of Christ is a keystone. True repentance is a keystone. Professing the Gospel is a keystone.
Road trips are great, I just prefer to take them by bus.