I moved many of my toons as low as the teens to Wakening Lands outside Kael and tagged faction off the groups that were factioning there. If no one was factioning, I'd log and play a different toon. Getting to kindly used to be really quick but I think they nerfed the WL giants' faction at some point. If a group is pulling the casters from the top of the hill, they give the most but be wary, they cast PB AOEs and Ice Comet that can one shot someone in the 30s.
Not sure what class you are but if you're a solo class, you can grind on the giant's wolves in EW & GD in the 30s.
If you had money to buy faction, you could turn in giant warrior helmets for faction too. They're about 50pp each though.
https://wiki.project1999.com/Giant_Helmets
Another option is to park your toon in Great Divide and find out when a guild is doing a ring war. There will be hundreds of giants for you to tag faction off of and I'd be shocked if you ever got aggro on any.