Well Crystal Tower 1 drops i80 gear and also gets you 200 Myth so about 2-3 solid runs pending the drops you'll probably be in the 70s in no time.

T1-T4 will suite your needs to get to 90

I'm currently i93 , i92 , i91 WHM DRG PLD respectively

the path I take is

Grind Bray till I'm able to buy some right side gear and get myself ready for Crystal Tower
Run that a few times get some drops and que for T1 and T2s
Get the 90 gear from there
by then you should have enough myth for more right side gear
and before you know it your iLvl is rocketing

Working a WAR right now and once you get your first high level character people sometimes pass on 90 gear that you can greed on I have full i70 for MNKS BLMS and BRDS and I don't have either of those classes in the works right now

So once you get here the grind gets a lot easier