- RPL you can fly an aircraft up to 1500kg vs PPL you can fly up to 5000kg
There is a MTOW restriction for the RPL but there is no such limitation for PPL. I believe there must have been one in the former versions of the regulations and the idea that PPL holders are limited to flying aircraft with an MTOW of 5700 kg is still being circulated but there is no such limit in the current ones.
As demid wrote, the limiting factor will most probably be the MTOW of your wallet. Most private operations involving a pilot and their mates will involve some form of cost sharing, in which case there is an explicit mention of 6 occupants, ie. the pilot + 5 passengers. Incidentally the wording says "sharing the costs equally". While it is a certainty that a private pilot may make no profit from the operation, no provision seems to be made for passengers wishing to just "chip in" and not sharing costs equally.
@ChaeBaee:
If money is a concern and hence making you consider the RPL + all endorsements, my advice is to consider this alternative: just
skip the RPL and all those endorsements altogether and go straight for the PPL. As a RPL is
no prerequisite for a PPL (as some schools would wrongly have you think – or are just happy to keep you confused), you can embark on the PPL right away. The syllabus up until navigations will be the same anyway but the good news is, you'll also just sit a single CASA exam (PPLA instead of RPLA). You'll cover the training of those radio, CTA/CTR, and navigation endorsements as part of the PPL training. If you add everything up, you'll find that going for PPL straightaway may take you a little longer to act as PIC but won't leave you much poorer and certainly will give you many more privileges.
Also worth noting: unless you're going to fly in your own aircraft, I found people reluctant to hire out to RPL holders. I can't blame them. The R in RPL means just that, you're a recreational pilot. Most will also ask for at least a PPL plus minimum time on type. Obviously you should always be able to hire from the school you trained with but that's a bit restrictive and schools charge you a fortune on VDO time. If you're flying out of a larger aerodrome, say YPJT, reach out to LAMEs. They often have a couple of airplanes that they're happy to hire out on flight switch at much, much lower hourly rates.