ALC 15, WVR 50, CUL 37, CRP 50.

These are the most important cross class for leveling. WVR is also great for making your own gear as you level, assuming you don't already have some. Byregot's Blessing is amazing, but I wouldn't consider it a requirement until 50+.

Maybe CUL 37 before WVR 50 (but get WVR 15) if you don't need to make your own gear.