The cautious move here would be to avoid them. Voyager is the fastest ship of a civalization that's at least 200 years ahead of the Kazon: it would be easy to do.
But if she does the cautious thing every time, she'll never get the ship home. Even if you ignore the agony of a 70 year voyage, they're unlikely to survive that long a trip through uncharted space with no support. She needs to take risks and hope for something to get them home faster: advanced warp technology, another member of the Caretaker's species, a wormhole, or something she hasn't thought of.
Admittedly, the Kazon don't seem very promising on the advanced technology front. But if they can establish friendly relations with the Kazon, it reduces the risk of travel through this part of space, and maybe they can ask around and get in touch with someone more advanced. And the risk here is pretty small: it only seems like a risk at all because the Kazon ship is acting like they know what they're doing. On the face of it, Voyager has them utterly outclassed.
"Let's see what they want."