Where can I get resources for developing for Mac OS Classic?
There used to be web versions of Inside Macintosh, alongside the PDFs, but I think those got trashed/concealed-too-well-to-find in the last shuffle of the documentation on the site.
Nope, here is a link:
https://web.archive.org/web/20130111022302/http://developer.apple.com/legacy/mac/library/documentation/macos8/mac8.html
Where can I get dev tools that can still target Classic?
You can get Apple's command-line (yes, for Classic) developer environment, MPW, from their FTP site: ftp://ftp.apple.com/developer/Tool_Chest/Core_Mac_OS_Tools/MPW_etc./MPW-GM_Images/MPW-GM.img.bin .
The shell is fairly UNIXish, except it uses a completely different punctuation alphabet. Your backslashes, bangs, and angle brackets are no good here. You generally should use Commando instead of trying to forge command lines yourself; type a command like “make” and hit option-return to get a GUI for it.
Note that you will have to run MPW inside your Classic environment; there is no native Mac OS X version. NeXT's Project Builder (now Xcode) replaced it in the move to Mac OS X.
Where can I get at least reference materials so I don't have to guess-and-check my way around Carbon/the System Toolbox?
Google search for site:developer.apple.com "inside macintosh. Good luck—they've started burying this stuff. Currently, Inside Macintosh matches will be nothing but PDF and will have titles like “IM: Text”.
There used to be web versions of Inside Macintosh, alongside the PDFs, but I think those got trashed/concealed-too-well-to-find in the last shuffle of the documentation on the site.
Carbon documentation is more available than Inside Macintosh, which refers to the old Toolbox documentation. Carbon docs will usually say whether something is only available on Mac OS X or not. If the docs don't say, the headers will. Note that Carbon requires CarbonLib on Classic, and the last version of that was 1.6.1, IIRC.
Are there any forums still running that would be open to answering old-school Mac questions for when I get stuck?
You could always ask on Stack Overflow.
I don't know where you can get CodeWarrior.
A lot of documentation is available in the Xcode documentation reader, though much is marked "legacy" etc. You might ask questions on Apple's carbon-dev mailing list; though classic questions may be considered off-topic, the list is pretty low traffic these days. You might also want to look at the wiki at carbondev.com.
I know almost zero about Classic Mac programming, but there's quite a few members of the 68kMLA that are programmers specifically working on Classic programs in general and even some very early System 6 apps specifically.
The developer/maintainer of Clasilla (http://www.floodgap.com/software/classilla/) Mozilla port to OS 9 is a profilic poster there and that is perhaps the last major project targeting the Classic environment, for example.
The wiki also has some programming resources, eg. http://68kmla.net/wiki/C/C%2B%2B_Programming_for_68k Not that great, but it has a download link for the MPW IDE.
Unfortunately, it is not specifically a programming forum but a Mac forum in general. Good luck though!
The site URL is http://68kmla.net