I worked up the same build for a gnome fey-pact warlock with the ranger multi-class feat yesterday ironically. I believe that Hunter's Quarry does work with the eldritch blast, as well as nearly all of the warlock's damage dealing spells. Hunter's Quarry doesn't specify the type of weapon or power to use with it (like rogue's Sneak Attack), so its a very good option for multi-classers.
In order to initially activate the hunter's quarry, you're warlock needs to be the closest enemy to you as your quarry (as a minor action once per encounter). Since you have hunter's quarry as a class feature from the warrior of the wild feat, I believe it remains active until the end of the encounter.
The Hunter's Quarry also should stack with Warlock's Curse, which enables you to do an extra +2d6 damage (more with certain ranger feats), on top of your normal spell damage.
Not a bad combo.