I can understand being concerned with running electrical, but low voltage is a snap, as you don't have to install boxes in the walls.
You can get the necessary equipment to install low-voltage wall plates at most home improvement stores. You'll need the wall plate, the correct inserts for it (they make 'em for F connectors (cable TV), RJ45 (twisted pair ethernet), RJ11 (phone), RCA plugs, and some can take extra wide inserts for HDMI, blanks to fill in any holes you won't be using, and a wall insert thing (not sure what it's officially called; it goes into the wall cavity to give you something to screw the wall plate down to.
You hold the insert where you want it (which is anywhere there isn't a stud, pipes, or electrial), trace it on the wall, then cut out with a drywall saw. Afix the insert.
You can then fish the lines through the wall cavity. As we're not trying to go horizontal, you can just use a decent sized nut tied to the end of a piece of string. Dangle it down, and grab it when it's at the lower hole. If you're trying to get it into a very small lower hole, or it's not exactly lined up with the other one and your hands aren't small enough, bend a wire coat hanger into a hook to grab the string. (note -- you want the string more than 2x the length you're going ... so you use one hand to wiggle the string if needed, while catching it with the other one.
Once you have the string fished through, tie the top end to something (you can temporarily place a bolt for the face plate into the wall insert, and tie off to that). Remove the nut from the lower end and tie it onto the cables you're fishing. Pull the string to bring the cables up. Attach the cables to the inside of the prepared faceplate. Bolt the faceplate to the wall.
Do whatever you need to do to terminate the stuff down below, and you're done.
Electrical is similar, but you have to put boxes in the wall which need to be attached to studs, so you have to plan your holes better. Fishing is more difficult, as you're trying to get it into one of the holes punched out of the box. (and I guess it's possible that there might be permit/inspection issues ... I'm not an electrician)