Gromp (with smite) > Blue > Wolves (wait for smite if you are not sure you can do without) > Recall (buy Stalker Blade and 3 health pots) > Red (chose between conserving smite or health pots) > Gank.
Grab red instead of wolves before backing if you consider it likely red would be stolen otherwise. Don't get red before backing otherwise, it is less efficient. Assuming you back after three camps, Gromp smite buff will have expired before you can do more with it regardless of whether you got it before or after blue, so you might as well maximize the time you will have blue.
I find Krugs to be too out of the way to pick up most of the time unless I am waiting on red to spawn with nothing else to do that would not make me arrive at it late.
Always arrive at blue/red by 10 after their respawns, and aim for sub 5 seconds. You should be within one camp's worth of xp till hitting 6 after getting the buff you started on a second time, and within one camp xp of 8 after claiming the second round of the buff you got second.
Swapping one of the three AP quints I used last season for a spell vamp quint was enough to make the above possible without a leash. No other changes to runes or masteries was needed. If you take spell vamp, camps with more creeps will leave you with more hp presuming you get all the creeps lined up for your Q.
Sample game link for runes/mastries: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1653009416/218693738?tab=overview
Clearing while staying high on hp becomes easy after warden's mail.
P.S.
To anyone who wants to know, the only aditional AP besides what I had in that game is the +5 from upgrading Sheen to Trinity Force. I just find AP is good for early game burst that makes ganks work out more often.