That might be rather more difficult than you might expect. Advent of Code uses quite a lot of 64-bit numbers. A bit of googling tells me C64 BASIC only supports 16-bit integers and 32-bit floats. I imagine the other BASICs have similar limitations.

I did 2023 Advent of Code with my own compiler and this was the biggest challenge I ran into. I only had 32-bit integers at the time so I had to manually implement 64-bit math and number formatting within the language to be able to do the puzzles. You would probably have to do the same in BASIC.