Car Audio in Early-A bodies?

Well ever since I bought my 66 dart I told myself I want to put atleast a aftermarket stereo in it. I am thinking in the glove box or making a little console on the ground for it? I dunno yet. Thats why I want some ideas. lol
Also maybe upgrade the speaker/speakers in the dash and maybe install some 6x9 in the rear deck.
Have any of you all done this before?
I would really appreciate pictures of how your set-up looks.
Also is it a pain in the but running new wire for everything and installing new speakers?
I have worked with lots of car audio before but not on anything this early of a model.
Anyone know what size of speaker is in the dash?
And how do I even access it?
I want to keep the factory AM radio in the dash to keep the old looks.
I am mainly concerned about the audio because once it is done I would like to take trips to car shows in this car. I would like to install Sirius/XM radio.
I needs some options instead of having only a AM radio.
Thanks guys!