Using the stock locations for the wire harness gromets is the best idea.
there are a few of them.
Two are located just inside of the fenders. (Easy to locate, you just pull the fender liners out, and you can see two very nice areas to pass wires on both sides of the vehicle. There are holes in the apron behind the strut towers where you can route the wires out of the engine bay, into the wheel well, and then into the dash panel area.)
Best way I've found of pulling wires is this.
Get a 3' or so section of 10 or 12ga copper wire. Bare wire. No insulation. Then using electrical tape, attach your wire to be pulled by taping it to the copper wire, for about 2" total. Make it nice and smooth, so it will pull easy through the rubber gromit cover.
With the sharp end of the wire, carefully push it through the gromit, and into the dash area. Make sure you don't catch other wires, or cut other insulation.
Then carefully pull the copper wire, and make sure the taped on wire your installing does not catch or tear the gromit too much.
When you have "fished" the wire through, you can remove the tape, and your done pulling that wire.
I've used this method to fish wires into the door panels via the rubber wire boots where the stock wires run, and other places where I don't want to have exposed wires hanging around looking lousy and being chaffed and cut over time. (Like I see so many have when mounting larger speakers in the doors, or other places.)
The best idea is if you have many wires to pull, tape them all on at the same time, and only do one pull that way. (Every wire is threaded through at the same time, and you have minimal tape work this way too.)
Good luck.