After a day of searching, I learned that in the details tab of the VirtualBox window (not the window that contains the VM itself), buried below the configuration information on the disk and memory, if you scroll to the bottom, is an entry on USB and you can enable it there.
The fix was, in the Linux host, to go to "System->Administration->Users and Groups" and then select "Manage Groups" and scroll down to "vboxusers" select that group name, click on the "Properties" menu, and then click on the "Group Members" checkbox to make sure you are in the vboxusers group. If you run "id" or similar from the command line, it will not list vboxusers as a group you are in because it only lists the first 8, but you are there.
And then reboot the Linux host! This horrifies me. A feature of Unix that is completely dynamically controlled now requires you to reboot the whole fucking machine. Truly, Linux is getting closer to becoming Windows every day.
That worked, but then I wasn't able to get the Control Panel->Wacom Tablet Properties" program to let me set the pad to have a left-handed orientation. The "mapping" tab simply did not show up. This was frustrating yet simple to fix. I had to touch the pen to the pad and then it recognized it and gave me a menu for pen/tablet options, not just the wheel.
The fix is to disable the mouse autocapture (leftcontrol-i as a shortcut). At that point, the mouse will work, the Wacom will work ONLY IN THE VM but it will function as a mouse and you'll get the pressure sensitivity when drawing.
The final bits I haven't figured out is how to calibrate the tablet, because I can't access the bottom of the screen currently, and how to get pressure sensitivity and orientation settings on linux, but they don't matter as much, since my main purpose is to use the pad with drawing tools under Windows for now.
I saw a description of the problem and the fix here. Basically, I uninstalled the WACOM driver, then downloaded adn ran CCleaner and then reinstalled the WACOM driver and things worked. Running the program I just deleted a few registery keys that it complained about, I left others there. After a reboot of the VM, the tablet worked fine.
This was way more painful than it had to be.