I think your best bet would be to start with Bard in the support role due to his versatility and challenge and thus, re-playability.
You might want to stick to some junglers that suit the role a bit better, such as
,
and
(or if you really like the off-meta stuff:
and
) etc.. The reason I say this is mainly because Karma jungle doesn't exactly have the health or damage sustain to clear as consistently as other junglers comparitively.
s Abilities in the Jungle {Referencing the lolWiki}: Right away you have her passive, Gathering Fire, which is wasted because it only activates on champions. Karma's Q, Inner Flame, does about 100-200 damage in the first grouping of levels with an approximate cooldown of 6.5 seconds. The average jungle camp has approx 1000 health within your first rounds of clearing, and with your other two abilities (W only works on champs and E is a shield) not doing damage you'll end up clearing camps on a ~10-15 second timer, which is insanely slow. Clear times like this also lead to losing more health and needing to back faster- with less money to boot.
With Bard on the horizon, many have speculated that his jungle was going to be amazing, but this assumption was quickly shut down by DanielZKlein, a champion designer at Riot. Replying, "we made sure jungle isn't his strongest role. He doesn't really have the damage to clear anything." {Source}.
I hope that helped in some sort of way!
Best of luck on the Rift,
AfroWairus