Thanks for the ideas, I'm going to give the engine degreaser and scrub brush a go first since that's the least "invasive" option so to speak. Really trying hard not to sand/paint if possible.

Sue, my VX spent her first 6-7 years in southwest PA before moving to Alexandria, Virginia. A bad area for corrosion for sure, but the two PA owners only put 12K miles on the clock TOTAL in those years, so there's only very light surface rust underneath (mostly on the muffler and hubs). Whatever's going on with the tank looks different to me - it's more of a sandy dirt color than an orangey rust.

I'll post before and after pics tomorrow. Gotta find the blasted memory card reader first though.