I have often been in your situation - that of making the best recording I could get on a limited budget with "simple equipment." I have used direct input in every case where I can. For something like your project, I would first record the drum machine connected directly to the cassette deck. Next, I would add the bass, again by direct patch cord connected to the deck. I would next record the guitar, again by a direct connection to the recorder. Finally, I would record the vocals using the two mikes. I don't know enough about the difference between the Shure 57 and 58 mikes to recommend one over the other; but you could play with those mikes a bit to see if one might be more suitable to one person's voice than the other. You might even want to do a bit of testing with these two mikes before you begin your "main recording project."
Ok, you have from me one plan which would not involve the purchase of more complex and expensive equipment; it also won't involve any fancy recording techniques to be learned. I have recorded enough multitrack recordings first on opel-reel equipment, then on cassette tapes, bouncing "takes" back and forth between two machines, and briefly - even between two CD home recorders - so that I know that you are probably going to make a recording of only demo quality (of course, I am assuming that your recording will be an analog recording rather than something like a DAT or the like). So in my opinion, you need not spend an unreasonable amount of effort worrying about "perfect recording quality."
Still, I am not at all a fan of putting a mike against a speaker to record something. In my teenage years at a residential school for the blind, we often recorded from a radio by putting the mike up to the radio speaker and rolling the tape. It worked, but, at least in my opinion, nowhere nearly as good as you could get using a direct cable to connect the source to the recorder. That's why, for my part, I still use direct connection between my music source and the recorder (or at least an input on a mixer). I use a mike ONLY when a mike is the only way to get the signal into the recorder (we obviously cannot connect a human voice directly to a recorder).
For me, a guitar might be a special case. I normally connect my guitar directly to the mixer which feeds my recorder; but I sometimes want to capture the acoustic qualities of the sound from my guitar to my recorder, requiring the miking of my guitar.
I wish you the best in your endeavor to record your band, and I hope the information above will at least encourage you in your effort to record simply and with modest equipment. If your work advances further in the recorded music arena, I'm sure you will eventually end up in a recording studio where they have all the great equipment to do a first-class recording for you. But until then, my advice is to use something like the method I have suggested to do the best you can for getting a good recording. If you are running in a cassette environment, even a multitrack cassette environment, there will be at least a minimal amount of wow and flutter introduced by the mechanical transport. DON'T WORRY ABOUT THAT!!! Just produce the best sound you can. If you do that, I maintain that you will have a product which you can enjoy for years to come.
I say that based on my experience: I have some old analog multitrack recordings of my "one-man band" which I stil play from time to time. I went so far as to make up names for my "band" as my music evolved through the years: Cousin Dave and the Pushbuttons, Bistable Flipflop (when I actually ran my guitar through a digital flipflop chip to produce a rough and not-to-reliable divide-by-2 to get the note an octave below the played note), and Hyperventilated Yoga on which I made a few somewhat "psychedelic" experimental recordings during which I actually used hyperventilation during the lead guitar track (mixture bending, as I called it) which among other things modified the "time base" in my mind to affect the rhythm of that track against the steady accompaniment track.
BY THE WAY, HYPERVENTILATED YOGA WENT OUT OF BUSINESS VERY QUICKLY FOR SAFETY REASONS, IF FOR NO OTHER REASON. Now, my wife would "have my head" if I did anymore with that "band" at my age of 76. But then, many of us did things in our teens and early 20s which were not in our best interest though they may have accomplished a purpose we thought good at the time. That does bring forth a possible question for others in home recording: In the same way that movie producers sometimes do risky things to make part of a movie, how far would we be willing to go in risky techniques or processes to get the desired effect on a recording? When it's all said and done on your project, though, the main thing is to HAVE FUN!
