I've done this twice because i reset my stats (on purpose) the first time I camped like a gooden, with shock charges, (put scavenger on for more) and it was so frustrating.
The second time I just stripped my class of all items except for perks and Greed 1/2/3 wildcards. 1st set of perks were Lightweight, Cold Blooded & Extreme Conditioning, then Ghost, Toughness & Dexterity and was running with my brother (same team) around the edge of the map just circling buildings every so often. I had much more fun doing it this way.
Just keep at it, I thought i would never get a gold knife but I did it, without cheating too.
Ronin was actually the hardest camo for me. I got so frustrated with it. I'd stab someone pick up their gun and then get 5-7 kills with it, before dying and none of them were the person I'd stabbed.
Instead of Toughness, wouldn't you rather use Scavenger? Get back some concussion grenades or shock charges? Is Toughness really helping you while using a knife only class?
Also, instead of Extreme Conditioning and Dexterity, if you are in "camper" mode, Awareness and Dead Silence might serve you better. I would suggest Dead Silence no matter what when running knife only mode.
Oh lol I am only 1 bloodthirsty off gold got all the kill camos easy found backstabbing easy same with ronin and all that and I find it easiest on nuke town hijacked and drone just get behind enemy lines by flanking kill everyone in the covered parts of that area and camp places like behind desks and lab things for the last one or two kills
It's a real pain to get but here was my loadout for doing it:
Tac Mask/Extreme Conditioning
Scorestreaks: UAV, CUAV, Guardian
Mostly I played DOM and focused on getting into a reasonably good traffic area coming out of their spawn with ample hiding corners. Use the concussion for those open field engagements and the rest of the time try to catch them off guard as they go past you. Hijacked is a good map to do this on if you take the underneath route to their side of the ship. I also like Hydro.
PS: Remember this setup when you go for the Riot Shield challenges.
Yeah I got my knife gold when the game first came out. I'm not sure how skilled you are with the knife but my loadout was:
Perks: Lightweight, flak jacket, fast hands, Extreme conditioning and tactical mask
For my equipment I used either a shock charge or concussion. I normally played either DOM or TDM. Mainly TDM though. I was good with my knife though and had a high k/d with it. You can do good pretty much all maps, but try maps with a lot of buildings like nuketown, standoff, hijacked, express. Those were the best for me. Hope this helps!