I believe that cc65 has a good linker that handles once set up for a platform/memory configuration. I don't know how efficient it is, but I bet that manually organizing code and data to minimize cross-page access will be more efficient.

On old (16-bit) x86 you used "far" pointers, which were larger for cross segment access. These were larger and I assume slower since they encoded both the within-segment address and the segment number.