Opal Farm Tip

If you're finding the hardcore mode a bit tough or just wanting to get through the story easier, then here's an idea.

Basics

First, get through the first boss, Patchy, then once the road to the beach (South-Eastern part of the map) is opened go there to the island with the big wooden submersible bunyip storage. By the big wooden building there are seven opal bags, 6 of them with 500 opals and one with a whoppin' 3'000 opals! The trick is, that you need a warp rang to get to the 3'000 opal bag.

This is where the beach is located

To get enough money for the Warperang (available at Sly's rang shop tower for 10'000 opals), you can start by farming the six 500 opal bags - here's how.

This is where the farming begins

Just get the 6x500 (=3'000) opals, then go to the Parrotbeard Cove race nearby. Going to the race will make the map reload with all the opal bags respawned. I've experienced this to be very fast, since I get generally a 1min 25s time, which is faster than driving far enough from the beach and returning to trigger the map reload. Alternatively, you can just go to the race and from the menu choose to leave it. But that's just for the really hasty ones...

Here's the location of Sly's rang shop

Now, to get the Warperang (10'000 opals) you need to have the Lasharang (4'000 opals), available in Burramudgee's rang shop. Then the Warperang becomes available in Sly's shop. Once you have the Warperang, you will get 6000 opals every time you farm the beach!

Life's a beach

So, without any further ado, happy farming! That Deadlyrang and all the health upgrades will soon be yours! It's gonna be GG from that point.

[Toof]

Even faster:
Cass' Run has a 3k bag right at the beginning on top of a spire. Exit the level and grab it. 75k in less than 15 minutes

[jexrutin]

Nice

[NiceAwesumDude]

I found a much faster method than this where you basically do a circuit at Frill Neck forest. First you climb up, and from the first bend in the path jump to the net floor of the next section. Find the ladder, climb up, and jump onto the next net section. Instead of climbing the first ladder, go to the back of this section and climb 2 ladders. Follow arrows to the next circular platform, behind it is a ladder. Climb it, and glide across to a 500 bag. Glide back to the platform you jumped from. Take the laso rings nearby to another 500 bag. From there glide in the direction of the end of the level to a circular platform. Jump down to a nearby 10 bag, and proceed to the floor of the final section. Climb up the ladder at the end, and backtrack to the point where you first encounter a gap in the path. Behind you should be a couple elevated platforms, and off to your right you should see a circular platform. Glide to it, and follow the platforms to a 3000 opal bag.

[jexrutin]

@Darkemu is it not working for you? Did you try going to the Parrotbeard Cove race and finish the race or exit it from the menu->leftmost sub-menu called Exit and from there "Leave Race"? For me it's still working as of today