...Try out the Eagle 'cause the non-profit version's free!
After reading that Fritzing was not recommended for SMT components, I loaded up EagleCAD again to give it a proper try this time. And I like it. Fritzing is still low-key, friendly, and amusing, and the graphics for the Breadboard mode are excellent for things like Instructables and also for working out gross component arrangement. But Eagle is serious CAD, with lots of good tools.
The organization of the parts libraries still confuses me, but I was able to at least create the custom parts I needed and place them in a directory where I could find them again. Above is the first attempt by the auto-router -- it looks surprisingly good, but I suspect I'll be hand-routing some traces.
Now that I've seen it is rout-able, I can work on the footprint a little more. I'm hoping to get it to the same width as a 2-pack of AAA batteries (even though my optimum design is now 3xAAA -- and that is also the version which is getting tested in a currently-running show).
The SOT-89 packages for the AMC7135's are the only SMDs on the board. I may turn some of the other discretes and blinkenlights into SMT components, but the big footprint hog right now is the I/O pins. I have them spaced right now for breadboard compatibility, but it may make more sense to move and condense them.
I'm also tempted to run off a 3-channel version with an ATtiny85 CPU. Smaller, sure, but also less parts to get wrong on my first venture into getting a board fabbed, and soldering my first SMDs.