First, if you’re going to farm Nulgath items for Void Highlord, Archfiend Doomlord, etc, I would highly recommend you buy AC’s to make your life a hell of a lot easier.

A shit ton of AC’s!

I’d go ahead and get your credit card or Paypal handy, and buy that 40k AC package for $99.95 (preferably when they have a 50% bonus sale).  Buy all three AC farming pets, Crag & Bamboozle, Drudgen the Assistant, and Swindle Bilk.  As for your IoDA, use it wisely.  Do not waste it on a farmable item, unless you plan to buy multiple 40k AC packages.  Use it on rare (no longer obtainable) items!  You will actually get two IoDA’s, you will get a bonus IoDA once you redeem the first one.  I would recommend you get Oblivion Blade of Nulgath (rare) for sure.  Maybe Nulgath Challenge Pet as well if you want to make gathering Blood Gems of Nulgath much easier.  Also, grind for Tendurr the Assistant from Dark Makai and get Nulgath (larvae) and the Sword of Nulgath from quests.  Pretty much all Nulgath farming pets are useful in some way.

Use Crag and Bamboozle and Oblivion Blade (rare) to gather items to convert to Relics of Chaos, 26 at a time, then use Supplies to Spin the Wheel of Chance on them.  Significantly faster than farming Escherion!  And utilize Drudgen the Salesman and Swindle's Return Policy as well (especially Swindle's Return Policy).  Swindle's Return Policy is really the only (since Crag and Bamboozle and Drudgen the Salesman also have all his other quests that are useful, that is his only useful quest that is exclusively on said pet), but a damn good reason, to have Swindle!

Some items will require The Assistant to acquire.  Although as many items as you can obtain, get for free from Supplies to Spin the Wheel of Chance!  Not all The Assistants are the same!  Drudgen's The Assistant is superior to Bamboozle's by far!  Drudgen's drop rates are significantly higher for items that drop exclusively from The Assistant than Bamboozle's!

A Refreshing Deal and A Poisonous Deal (especially A Refreshing Deal) are very nice if you have the Nulgath Challenge pet for acquiring Blood Gems of Nulgath.  If you don't get the Nulgath Challenge pet, I would use Bamboozle to convert 15 diamonds to an Unidentified 13 then Drudgen to convert an Unidentified 13 into a Blood Gem.  Except for Blood Gems (which take 10 days to max out with the Nulgath Challenge Pet dailies if you're lazy, faster if you do the Assisting Oblivion Blade from Tendurr the Assistant once you max out the others), the others can be maxed out in a few hours.

Not every year but some years in January, the game offers the Bounty Hunter farming pet.  I suggest you purchase it when offered.  The Crimson and Astral orb pets are slightly better than the Bounty Hunter as far as how fast they are (their drop rate for totems and fiend tokens is lower though, only real difference), although they require an IoDA.

If you do not get AC's, I do not know how to advise you, as I got AC's immediately to buy said pets, and got the IoDA's later for more farming pets, and don't regret it.  If you do, you have a LONG road ahead of you!