Wow, yes looks like 90% of VR6 heads you see today! a little corrosion is normal for these old girls.....
I have seen similar repairs with JB weld or equivalent to fill in the void - after all the head gasket will compress it back again.
get whole headed dipped and cleaned, repair corrosion, and get skimmed should be job done, alternatively look on our classifieds for other second hand heads in better condition but I can tell you most heads will be like that this day and age