You sound so sure. Why do you think so? A few believe it was written earlier, but the prevailing consensus is that it was written around 95 ad. Check out this link for a decent evaluation.
Another question that comes to mind is that since the Temple and it's records were destroyed utterly in AD70, and with it all of the records of who was who, just how do they know who is a true Israelite any more? How will they select their high priest without a descendant of the tribe of Levi?
First of all, God knows, and don't you think He has it in His power to make sure they return? And this is wild, but they reportedly are able to determine who is of priestly descent by their dna. Doesn't surprise me though, just reminds me of the wonders of God.
Why do I think so? Because it fits with the history we have from that time, mainly that of Flavious Josephus, and also because it was the prevailent view of the 1st-4th century church. Not till after 450AD did a Futurist view show up, and even then it was speculative based on the author being a John other than the Apostle John.
I'll agree that amoung Futurist and possibly some others, the later date is the concensus, in fact it has to be for their view to have relevance.
The Historist, Idealist and Preterist views are and have always been that all of the books of the NT were written before AD 70.
In addition to the historical account of Josephus(specifically The War with the Jews, you might find the online book Before Jerusalem Fell interesting.
As for the selection of the priest, it is irrelevant to me, as Christ is and evermore shall be the High Priest. That's why the Red Heifer is a Red Herring(i.e. Old Covenant vs. New Covenant).
I realize of course that your views likely differ, and that is one of the things that make life interesting. It would be boring if we all agreed on everything all the time.