To get to the point: Physical RKs (i.e., RKs built around skills other than Dragon Breath) have no truly practical option for leveling in the 181 - 185 range, which is all about efficiently grouping and killing mobs of monsters in Nogg 3 and AGH (soloing monsters in AGH "works" - for sufficiently modest expectations of "works" - until about 180)
The crux of the problem is Ignition Break, which is supposed to be the capstone AoE skill for the Physical RK subclass, but is unviable for leveling past 175+ due to a crippling dual handicap of middling max damage and god-awful 2 second cooldown. While IB's max damage could certainly use a shot in the arm, the second flaw, its cooldown, is what definitively sinks it as a leveling tool after 175.
The good news: Some googling suggests that there are at least three pieces of gear in the Extended RO Cinematic Universe™ that significantly reduce IB Cooldown:
- Volar : Reduces Ignition Break cooldown by 1 second.
- Ignition Shadow Earring: Reduces Ignition Break cooldown by 0.2 seconds, and then by an additional 0.1 seconds per 3 refine levels.
- Automatic Module (Wave Break): Reduces Ignition Break cooldown by .25 seconds each.