I'm not sure how you'll accomplish this. I'd suggest you consider a simpler way, of which there are several.

If there is a way without having to directly program a chip, remove it from the programmer and insert it into the system, let me know.
there is: buy an ISP chip.

My code will mainly determine that, but because of the interrupt vectors and other factors, I will definitely use address 0 through 2.

My code is less than 64 bytes in length, but it won't be all bunched together, because the interrupt vectors are fixed at certain locations.
I doubt "My code" uses interrupts, so what is the issue?

I do anything like this in the future.
Basing "the future" on 10 yars or more old technology, that would be cr naah lunatic

Have you ever written a program in assembly language ... ANY assembly language?

Yes, and I made my own 8051 assembler too.
with plenty of free assemblers available, why do you do that. Is this the same reason thet you refuse to use technology that would solve your problems in an instant?

Do you know what top-down design methodology is?

Somewhat
change that to a YES before going on.

Erik