don't have the game on the ps3. So what else?

Do you have a ps3 still and some ps3 games? If so all you need to do is download a modded game save. Lots of em online. I think a guy named viper something has a good one on youtube maybe. Anyways what ya do is get a program called brute force save data for ps3 There should be a good tut with download link on youtube. you load a game save from any ps3 game you still have. Pop it on a usb that is properly formated. You know it's properly formatted because it lets you access it on ps3. Then load it up on your pc and use PARAM.sfo editor which comes with brute for and get the information from the save for your ps3/account then you load up the modded save and using the information from the other save resign it to your ps3 and rebuild it if need be in brute force. Then you make a back up of your ps4 save. Always make back ups. Then you simply load the flash drive with the modded ps3 save into your ps4 and import the save just like you would a reguler d3 ps3 save. Then send the items/resources you need to an alt via in game mail, restore your original save and send the items back to yourself. Pleanty of keys or what ever else you need.

thanks for the very detailed instructions. While I am willing to use, in game expliots, cross saves, cross play and boosting to get trophies. Downloading other peoples saves is a line I don't plan on crossing for trophies. 

from what I've read I need to play regular rifts to get the keystones for the great rifts.

Everyone needs a line and I respect that. You wanted the easiest and fastest way possible and that by far is the easiest way. Only other thing I can think is to use an alt to dupe keystones or Horadric Caches or both and just keep sending them to yourself until you have adequate shards and keys.

...for a moment I wanted to get all moralistic and crap...and then I remembered that I duped Astrea's soul in Demon's Souls because I really, REALLY did not feel like doing a fourth playthrough.

Also, yay for over 500 posts. It's been a while since I've last been on a forum this much.

LOVED platinuming this sucka - a great feeling of satisfaction!! Huge love for the couple of players who let me borrow a couple of armour pieces I needed... One of my fav games ever!

At this point I'm too far into this platinum to back out. Almost got my 3rd lvl 70 character. Three more to go, but two of them are already level 38 - my gf's original chars -.

Well if you're shooting for the platinum, that means you've got plenty of Normal Rift keys, the only way to get Greater Rift keys is from Rift Guardians so you have to pick a difficulty where you can clear the rift relatively easily. You can do Normal difficulty Rifts if all you want is the GR keys but I prefer to find a balance between the difficulty I can handle and the time it takes to clear the rift. This way you might get good drops while farming the GR keys.

An added bonus is that you'll also get Blood Shards while farming your keys which you can trade with Kalada to complete a Set or get a great Legendary piece.

Have played alot of D3 , around 600 in paragon and still havent Platinum it. Dont see why you should cheat just to get platium. I hated playing online since most high lvl cheated, so only played single player or with friends.

And once you get decent gear all difficulties exep maybe really high greatest rift are super easy.

But havent played latetely so maybe they changera something

I used to consider that the game was too easy.
Then I died 7 times on a Greater Rift lvl 18 I think on Torment II. Yeah, that'll make me adopt a more serious gaming position on the sofa.