I'm not sure what the point of Heaven without Jesus is, but if that's how you're determined to do it, then I guess you could put the focus on God, either as creator or, if it fits your storyworld's theology, as the wholeness of the Trinity.
Think about the purpose of heaven. It is the place God lives, and where the dead (in Christian theology, the dead in Christ) wait with him until he brings about the New Heaven and the New Earth in the end times. The the prerequisite for being with him there is faith. In Christian theology, we would say faith in Jesus, but if you don't want to go there you could just say faith in God.
Above all, keep in mind that entrance into Heaven or exclusion from it is NEVER based on works, at least not in Christian theology. It is TOTALLY based on faith and grace, lest no one should boast (Eph. 2:8-9).