Thanks for the extra suggestions, everyone. I got 2 books on 68000 programming in the mail that I bought second hand recently and am now reading up on the 68000. Sure is nice to at least be able to read 68000 assembly properly and to learn about the CPU itself.
I'm also reading some relevant chapters in the 'Amiga ROM Kernel Reference: Libraries' book, which will be followed by 'Devices' of the same series.
I think I have some original SAS/C disks somewhere that came with an A3000 I bought last year and a cutdown version of DevPac2 on an Amiga Format coverdisk, which should get me started soon. Hope to get some more spare time during the holidays and actually try some 'classic' coding.