I got some controls working with AdvMame. I need to go through and get a few pages on the AdvMame configuration settings, since I wasn't sure what to use to specify controls for the trackball or spinner. I also had a problem because my "Coin One" button pauses the game no matter what. This leads to funky issues. For instance, on one game, I kept trying to put in a coin by pressing that button and it just paused the game. On another game, it would add a coin to the count, but also pause the game until I pressed it again.
I also found that AdvMame can read a keyboard as if it's two controllers. Since I can change my controller from "B Input Mode" to "Keyboard Mode" (I'm guessing "B" means "Button," but I don't know.) From what I can see, just reading the TAB menu on AdvMame, I might have success using Keyboard mode and letting the keyboard act like two controllers.
That also raises another question I'm going to have to spend time searching for: Mame-Libretro(2003) vs. AdvMame. Do I keep both on the system? I'm not sure if they'll both work consistently with the controller in one mode. AdvMame seems to work better, including using sound sample files easily, and the ROM set that works with AdvMame has more games in it. But that's a whole other issue to explore. Ideally I'd like to get my controller working in Keyboard and B Mode in both AdvMame and Mame-Libretro, but if I can get it to do everything in one form, I'll call it a day.