Note that you've got 32k of non-paged memory located at 4000-7FFF and from C000 to FFFF. When you try to access data from those addresses, the value in PPAGE is irrelevant. So unless you have more than 32k of constant data, you won't have to worry about PPAGE. Where the code using the constants is located doesn't matter.
What you do need to be careful with though, is the use of JSR/CALL and RTS/RTC, but that's another topic.