http://www.blueletterbible.org/kjv/Mat/Mat024.html#top
Mat 24:15 When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand:)
Mat 24:16 Then let them which be in Judaea flee into the mountains:
Mat 24:17 Let him which is on the housetop not come down to take any thing out of his house:
Mat 24:18 Neither let him which is in the field return back to take his clothes.
Revelation - Chapter 21
Rev 21:1 And I saw a new heaven and a NEW earth: for the first heaven and the first earth were PASSED AWAY; and there was no more sea.
Rev 21:2 And I John saw the holy city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband.
Rev 21:3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God [is] with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, [and be] their God.
Rev 21:4 And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away.
Rev 21:5 And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful.
Rev 21:6 And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely.
If you go pass v18, which you did not, it states that "unless those days had been shorten..." (vs 23) "false Christs" would arise trying to mislead the elect(vs 24). I though the "Anti-Christ" already had. I'd especially call your attention to his point in Luke where it states "when you see Jerusalem surrounded by armies.." (Luke 21:20) which I found interesting.
To be perfectly honest, the Olivet Discourse always was a muddled mess in my mind simply because of the sequences of the verses. Topcat's author and the above post in my mind provides a reasonable and historic interpretation to the Olivet Discourse. How you are fitting Revelation 21 with the Olivet Discourse baffles me as it is the establishment of the new Heaven and Earth.