I am installing a 30amp breaker into my box, which is located on the side of the house. I see a hole where all the wires leave the box and go into the house, but I am unsure where those wires go.

1) Is there a standard way wires travel from the circuit box into the walls?
2) When wires leave the box, do they go into some kind of conduit, or do they just go between the drywall and the studs?
3) Since there is no way for me to access the inside of my wall, no crawlspace, I am going to punch a hole on the other side of the breaker box, which is the garage, and take the wire out from that end. Do you guys have any suggestion on the best way to measure so I can punch the hole in the right place? For example, should I punch the hole at floor level, or near towards the ceiling?

I am installing a 30amp 10/3 120/240v wire for my Dryer, which is practically on the other side of the breaker box. Separate by the garage wall.

Thanks for any suggestions.

Further dryer receptacles as old work boxes (attached only to the drywall itself), are a bit flimsy for the size of that plug. Taking down a little drywall will let you attach it to the stud.