Not only can you pick up PPU trips out of base (after 1300 LBT) you can also SRM about of base. Call crew desk and ask them to put you on the list, explain that you’re based elsewhere. I’ll caveat this with, I haven’t dont it in a while so that may have changed. The catch is you’ll be last to get called behind all pilots in base on the list (so likely never). The trips will be so short notice that unless you’re already there you prob won’t be able to do it anyway.