Why can’t I see any detail on planets?
Planets are really small!  (when seen from Earth) 

Deepskywatch has an example of what can been seen with a 150mm reflector and a magnification of x180 (ie slightly more than your Astromaster which has a 130mm main mirror, and comes with a x65 eyepiece)



You should be able to see the 4 moons, and one or two bands on Jupiter. This assumes good "seeing" (the amount of turbulence in the air, not the same as the clarity of the air), and a properly collimated and aligned telescope lens.

There are lots of other good deep-sky targets that benefit more from a dark sky than the planets.