Final Update: Seattle's once-in-a-generation crazy winter settled in, and so I finally just wound up taking my new ST1100 down to Hinshaw's Motorcycle in Auburn, WA and having them give it the ole once-over. They are a good shop, trustworthy, and I have done business with them for a couple of years, so I know what to push back on, and what to just knuckle down and pay for.
The "groaning" was, of course, exactly what everyone said... nothing to be worried about. So if it groans at me now, I pop open the fuel cap, and instantly equalize the pressure. No biggie.
I wound up having the shop replace both switch assemblies on the left and right handlebar.
They also replaced the leaking(!!) fuel pump.
And mentioned that the gas tank was full of rust.... but when the tech took the tank off, it got mis-handled somehow, and damaged. So they replaced my fuel tank FOR FREE! Yay! No more rust!
All fluids and filters got changed.
And - a mere $2k later *cough* - I have basically a brand new bike. Tires are good. The new Clearview fairing is brilliant. And now that I saw the post about bending the clips back into shape on the luggage rack, I'll get that left side saddle bag to sit properly finally.
And Jim Van will be happy to hear that I have no mice, either.