Some STAR procedures provide altitude limits on them, so ATC would say:
Descend via the X arrival
All of the needed restrictions are published on the chart. Since the CAMRN4 does not provide hard limits (just "expect" altitudes), ATC will provide pilots with altitude restrictions per other traffic and their SOP, such as:
Cross HOGGS at FL180
For most arrival procedures, it wouldn't be critical to restrict altitude at every fix along the route. Any important restrictions would be included. If a fix doesn't list altitude restrictions, then no special restrictions apply. It's up to ATC to provide additional restrictions as required. Once an aircraft gets to the approach phase, altitude becomes more critical, and there will be more restrictions noted.
If you imagine a flight path through space, only two points are required to define a line. You could even consider the top of descent as one of the points, determined by the aircraft's rate of descent. Altitudes at the other points can be determined by that path. A modern Flight Management Computer is able to provide Vertical Navigation guidance, so that an airplane will basically follow that path to cross fixes at the required altitudes. Without this system, pilots would be expected to either manually adjust rate of descent to follow the restrictions, to perform an idle descent to the next restriction. On the CAMRN4, it would be fine by the chart to dive to 11000 after HOGGS, but this would not be expected or efficient. Some arrival procedures may be steeper or shallower than an open descent.
Note that the CAMRN4 says it is applicable to turbojet aircraft only, and pilots should expect FL180 at HOGGS and 11000 at CAMRN. Pretty much any aircraft on this STAR will be well above that 6000 MEA. If they do happen to be that low, the MEA should keep them clear of the Atlantic City class C that extends up to 4100 ft. Other than that the general minimum altitudes in the area would apply.