The 488 will record 4 tracks simultaneously, max.
You could do what you outlined above, if you considered having at least 3 outboard preamps to accommodate 5 mics, because the 488 only has 2 active mic preamps onboard, & the rest of the inputs are line level.
Given that you've scrounged together 3 preamps, then you could indeed send all [4] drum mics to one tape track, and guitar mic to another tape track. Also, you could just as easily send [4] drum mics to a stereo pair of tape tracks, 1/2 or 3/4, and send the guitar mic separately to it's own track. It's doable.
The 488 records up to 4 tracks simultaneously, and has two onboard mic preamps, & 12 input mixer, total, into 8 tracks on cassette tape. Those are design concepts that either drive or limit what you'll do on the 488, in the way of production.
Other Portastudios have more onboard preamps, FI, the 488mkII has 4, and the 424mkII/III has 4 & 6, respectively.
So goes the thought, further, of using an outboard mixer with the proper number of mic preamps, to do the submixing of drums, and send the submixed drum signal to the 488 in stereo, at line level. That's reflected in your anonymous quote, of using two 4-tracks,... in which one is a submixer to the other. Most 4-track Portastudios make great submixers, as well, which is why it pays to have a couple of them laying around.