Warhead Junction is an excellent Murky Map mostly because it so big. Its a huge pain for the enemy team to come hunt you down when you are clear across the map.
Murky lives on the lower lane on this map. Occasionally going up to mid to cause some havoc. I avoid the top half of the map because of the watch tower. It's just a pain trying to keep retaking it and detract from pushing lanes.
The easy camps on the lower lane are easy to capture so I do not bother with bribe. Instead I take Egg Hunt. The stealth is handy because it hides you on the mini map. This lets me place an egg deep in enemy territory. I can also place a fake egg near the bosses too ensure that the enemy team does not try to sneak it.
Endless Murlocks and be usefull for taking out unattend keeps. I usally go with Octo Grab as there are lots of little 1v1 or 2v2 skirmeshes.
I prefer slime build slightly over split push build on this map. Mostly because the lanes are so far apart. But have had success with push build when I get a nightmare comp for Murky.