I am all set up to go in Oct. However, I am on the hunt for an appropriate bike: pre-1987.

What should I be looking for? Specific brands and models to help me search on the auction sites or craigslist would be helpful.

Also, for those that have done L'Eroica, any tips or suggestions?

Thanks!

You are going to Europe, you can afford that. But you feel the need to use a bike that is a quarter century old and you haven't got it yet.

This has disaster written all over it like a billboard lit up by ten foot tall neon letters.

Discover the 90's... Look for a old Trek 520. There is another, older Trek touring bike that's nice, but rare, I don't remember the name, but the name suggest touring.

You could also get a good hardtail steel Mtn bike and convert it to use for touring.
That would be pretty cheap, and easier to find. Don't just grab the first one that comes along. Learn what the good bikes were back then, and look for them. A few had short chainstays, avoid them.

I'd find some used drop bars and bar end shifters, throw on some good touring tires, prob replace the drivetrain.
Which assumes it is also getting a total tuneup.