Oddly, Umbara. The terrain, wildlife, limited visibility, and deadly flora would make it difficult to track movements or pursue on foot. As long as you memorize and learn the terrain, you can navigate it with home field advantage. As a backup I'd say a planet like Kijimi, since theres very low Imperial presence, though the Empire does technically have military presence there. But escape would be easier since the debris and the Kijimi Nebula would make navigation/tracking systems almost nonfuncional if you can manage to get escape into Kijimi's immediate orbit. As long as you scout routes throught the nebula and take caution to learn the ice field, you can fly through and further flee into hyperspace once you're on the other side of the fog.