It can't hurt to have Vs stashed ahead of time anyways. That's time you don't need to spend farming red scrips. I'd also recommend stashing some IVs too.

As for what to stockpile, it's rather difficult to tell exactly what. Stuff for level 60 crafts for GC turnins are a good choice, as are the most common HW mats. I've been stocking up on ores, sands, and logs from HW for the most part.