Ok, this might be a long post but here goes.....
With any LED application the main goal, or at least IMO, is to 'hide' the light rods. You want to make it so you don't see the actual LED, you want to see the 'glow' from them. Under the dash is easy (zip straps/ties will be your best friend) and the same goes for the rear passenger floor ones (you can zip them to the back bottom frame of the seat. Just make sure the rear passengers don't like playing 'footsies' with the bottom of the seats. So we got to where you should probably install the tubes. Best thing to do with hiding wires is to run them under the carpet if possible or in this case it will be easier to just run them along the center console. You can remove the entire center console very easily, a few screws here and there (two in the cup holders) and one in the back cup holder (hidden by a little cover you can pry up). If you have an armrest you have to remove that first, then there are some screws inside there I think, can't remember but it's very very basic dismantling of the center console. If anyone installed their own short throw shifter they know what I am talking about.
Anyway, once you get that all out of the way, run the wires from the back tubes up under the seat rail (very important cause you don't want to 'slide' the seat back over the wires) and up towards the center console. You can then run the wires up between the seats. Make sure you keep the wires away from the shift linkage and anything else in there. Use zip straps to tie them to other 'things' along the way to keep the wires in place. If the wires are not long enough, all you need to do is get a similar type wire (same gauge, if you don't know what I mean, take the led and wire down to an automotive shop, tell them what you are doing and they will help you find the right wire). You will also need some 'butt connectors', yes that is what they are called for the same gauge wire you have. A wiring tool (used to crimp the butt connectors and to strip back the rubber around the wire) works awesome right about now but you can always do it the Canadian way (not recommended) and use your teeth to strip the wire and use some old pliers to crimp the butt connector. Anyway...lol... you get the idea. If the wire is to short, strip back about a 1/4", little less of the rubber on the LED wire and do the same on the new wire. Slide the stripped LED wire into one end of the butt connector and then slide the stripped new wire into the other end. While holding them in the butt connector (make sure the rubber is flush with the ends of the butt connector so you don't have the possibility of shorting it all out) and crimp the butt connector at each end then at the middle. When you crimp it, the steel shaft inside the butt connector compresses and 'traps' both ends of the wire inside and also cause it's steel, can conduct electricity between the two. Anyway that is how to extend the wires. Now to the fronts.
Same as the backs, get all the wires run to where you want, eventually you want all the wires run up together to the same spot near the front near the cup holders but below them. Find out where you want the switch to go and use the amount of wire you need, plus a little extra to get the switch to that spot. Also, wherever you are planning on putting the switch or switches is up to you (I still recommend putting them in the fuse panel door on the dash just below the headlight switch on the drivers side and I also recommend using one switch for all the interior lights) but anyway, you are going to want to run the postive LED wires together (if your using one switch) and if your using two, run the two front LED postive wires together and the two back LED postive wires together (twist them together). Next, you are going to want to wire ALL the negative LED wires together and ground them in the same place. Easiest would be to find another ground wire and splice into that ground (usually you can just unscrew the screw or bolt holding it down and wrap the wire around it). What you want to have is all the ground wires twisted together. You can buy an 'end' to put on the wires that are twisted together (electrical pieces, you can buy them where you buy the wire) there is one that has a ring of steel and a plastic end piece that is what you would crimp after you slip it on the ends of the twisted wire (called a ring terminal). You want to basically get a good ground, if you make your own, scrape the paint off the metal surface so that there is a metal to metal contact with the ring terminal on the twisted wire and the steel of the car. Use a self tapping screw and your done. You can also ground it to the battery (negative terminal '-') or like I said and the preferred way, find a ground to ground it to that is already there. Anyway.... lets sum things up so far....
You got your ground in place, you got your positive wires twisted together. You need to connect the positive LED wires to the switch. Most switches it doesn't matter what end you put the positive LED wires on. If you use a 'lighted' switch you will have three terminals (PM me if you need to know about that) but anyway, attach the LED wires to the switch (using those typical electrical wire ends (also depends on the switch. You can also solder them on to the switch as well, there are many ways. Once that is in place (if one switch, all LED postive wires to one terminal on the switch) and (if two switches, two LED front positive wires twisted together to one terminal on one switch and the two LED back positive wires twisted together to one terminal on the other switch).
Anyway so what you have now is all the LED wires are hooked up to something. You got all the LED negative wires grounded together to the chasis and you got the LED positive wires run to the switch or switches.
Now you need to get power to the LED tubes.... ok finger break... back in the next post.....