This might sound strange; but it seems to me we make our own hell, or heaven, in this life, and we begin to live in it in this life. Letting go of sin is simply choosing to live in God's law of love: To love God with our whole heart and soul and mind; and our neighbor as ourself, for the love of God.
I, too, have always found C. S. Lewis' theology to be morally satisfying and sound, a model of sanity. He shows that the tuning of the mind and soul to God is a free choice:
"But though it was easy to twist one’s mind into the diabolical attitude, it was not fun, or not for long. The strain produced a sort of spiritual cramp. The work into which I had to project myself while I spoke through Screwtape was all dust, grit, thirst, and itch. Every trace of beauty, freshness, and geniality had to be excluded. It almost smothered me before I was done."
Hell as a state of mind and soul is "all dust, grit, thirst, and itch" because it is utterly, absolutely devoid of "beauty, freshness, and geniality." That is, it is devoid of all God's goodness, grace, and light; and so the soul truly suffers there, in this life and the next.
Or so it seems to me, FWIW. Thanks for writing, CobaltBlue.