I like both those books, @ZenNudist - especially NT Wright's Surprised by Hope, which very much reframes the whole idea of a kind of floaty disembodied heaven where we sit around for eternity (not to mention the idea of hell as eternal, conscious torment.) I like the way he writes of our redemption/salvation as something as much for the now as the not yet - as something transformative which changes communities and brings the kingdom to earth, rather than being focused only on 'going to heaven' - and then about how God's plan as expressed in scripture is to restore and heal, to renew the earth, to bring hope where we are rather than only in where we might end up.
The idea of eternity is a difficult one to get our heads around, isn't it. If I think about it too long it blows my mind, and I think no, thanks, I don't want to be never ending. But that's only in my experience of temporal things, and the idea that God is outside time is helpful - therefore his plan for humanity is ultimately to be part of that, where there will be no more pain, mourning etc, but we have no idea what it will look like. As a Christian, though, I do find hope for the future sustaining, in terms of eternity, because my experience of God is of absolute, unconditional love, and peace beyond understanding, and sometimes incredible joy ('joy unspeakable', C S Lewis called it.) Therefore I know these are what God longs for us as humans to know in full - it says in one of the epistles (can't remember which offhand) that we see through a glass darkly, and will one day see in full, and everything will become clear.
As well as that, the idea of justice is so very compelling, of all that has been done that is evil being held to account, of all those who have been abused and oppressed and hated and lessened recieving justice, at last. It's something that can be very sustaining for those living in really difficult situations.
I do think faith is sustaining for this life, but hope gives us a glimpse of what could be, too, and I know and trust that the God who loves so passionately will bring us into something we can't even imagine, but will be beautiful and just and exciting. I don't tend to spend too much time thinking about it, though, because there are things that matter far more in this life, like feeding the hungry and setting the oppressed free, like forgiving and reconciling, and like pursuing my worship of and relationship with God in the now where I am, even though that is so often very painful.
It's great that you're on a journey and thinking about these things. I do find that scripture points so often to that hope, and that brings an extra kind of peace, a soothing in our deepest places, a sense of rest in the storm.