'Preterism' is the view that many of the prophecies we find in the new testament are about the events of AD70 when God judged faithless, Messiah-crucifying, Roman-colluding, Church-persecuting Judaism, in effect 'divorcing' Old Israel to make ready for marrying New Israel. It therefore reads many of the 'Jesus is coming real soon' texts as being about his coming in judgment in AD70, without denying that he will come again to judge the living and the dead at the close of history.
So, what might a preterist reading of 2 Peter 3 look like?
1. The day of the Lord is the AD70 judgment on Jerusalem (3:10).
It will after all, come on the scoffers of Peter's generation (3:2-7), who're probably identified with the false prophets of chapter 2.
2.The burning of the heavenly bodies/ the destruction of the heavens and earth that now exist (3:7, 10) refers to the judgment fires on Jerusalem.
God often abolishes and re-makes the world/shakes the heavenly bodies and so on. See Haggai 2:6-7 and 20-23, and Isaiah 13. All these texts clearly refer to the political and covenantal re-alignment of the world. In AD70 the old covenant Jerusalem/temple-centred world was abolished. This is a part of very common bible symbolism in which the heavenly bodies (stars etc.) are used to represent powers and authorities, both on earth and in the heavenly realms.
3. The new creation refers to our post-AD70 world.
Old Israel-centric world gone, Christ and New Israel-centric world begun. We are living in the age of Christ's rule, through his new covenant people, the reign of righteousness which is progressively spreading throughout history as people come to bow the knee to the world's new King.
This seems perhaps the hardest bit to swallow, but, remember
a. The new creation began with Christ's resurrection. (Surely, everyone believes this).
b. The new creation has also begun in Christians who are raised with Christ in some sense now. (Surely everyone believes this).
c. The legal/covenantal precedes the cosmic. i.e. the new heavens and the new earth have legally begun, the big covenantal shift has occured, the world is a new world because it has new government - Christ, and in him, his people. The cosmic effects of this new government won't be physically experienced (i.e. no more crying/pain/death/curse/sinners) until Jesus returns to earth and consummates the new creation. But a consummation is a consummation of something which has already legally been established.
d. So, to speak of the new creation as having already arrived is not intrinsically an over-realised eschatology.
e. And, after all, unless the new creation in some sense is 'here' now in our world which still has sinful people and death, don't we have a massive problem with Isaiah 65 which says that it is.
Do I still have questions about such a reading? Yes. Do I think that AD70 looms very large in the New Testament, such that such a reading demands attention and careful thought? Yes. See Galatians 4:24-31 and Hebrews 8:13.
More can be found on preterism here, here and here.