Magus Falls and Maguuma Wastes ?
I can’t seem to find a portal to get into those areas.
Because there aren’t any.
It may be in that green area in the next area to be released. That seems like the likely location for it unless they change the map around a bit prior to the next release.
If you are looking for the new areas they just opened up over the last couple of weeks, head over to Brisban Wildlands – the portal is in the lower left of the map.