Remove 2004 LC100 driverside cargo area side trim

From what i remember it just all pops off Start by pulling door seal off in required place and work it off It has plastic plugs that just pop out. will also have to pull carpet back as it tucks under it best to take panel across rear floor off first about 8 screws in it Dont have to take trim around window off.
You may be able to pop it along under window and just drop a cable in behind it and get it down to the grommet. I did it for a reversing camera which I fitted in the top taildoor

Buy a few of the plugs as they have a habit of breaking or deforming and dont hold on replacing Not expensive at a Toyota dealer.

Will be interesting with drawers Best to try just popping the top and pulling it out an inch or two

What Tom said is correct. The side trim is held in place at the bottom by the floor mat. To completely remove the side trim, the drawers and floor mat must come out. It is possible to remove the side trim from the top only and do the wiring that way if you have long skinny arms. To do this pull away from the top and work around the edges. You are sure to bust some clips.

I cant remember as its 6 years since I sold mine I remember it only has those funny little inserts in the side which are different on each side and dont go right through Other wise a piece of hard wire up from that grommet which is a sort of a 4" x 2" oval one isnt it Pull it out and try to fiddle the wire up till you can see it from the top of the side panel.Or down from the top if you measure it you will have an idea of how far to go.
The best thing to use is the plastic insert that goes between sheets of flooring as its tough and flexible and can be manuevered a bit
Question Why are you putting a cable for a TPMS Most run to the trailer by wireless Mine did although I had a booster box in the front of the van. You can have it for the postage if your unit runs 433mhz

Here is an alternative if your cable is long enough There is an irregular triangular shaped stamped part in the firewall in front of the driver. Check inside there is nothing behind it and you can drill a hole in it, put a grommet in and run the cable through it and down to the right hand chassis rail. You will find a wiring loom running along the top of it.. Cable tie your cable to that and out the back. I did that with my heavy power cables for the van.

I have a 100 series and installed the rial for the Inawise 203 in the rear cargo area. As we have draws, I just let the magnat attach to the rear draw frame at the rear seat member, no problem with signal transmission.
Removing the trim as above, pull out from top and drop cable in as required.

Thanks to all who responded.
As I said in my original post one of the problems is the draw/cargo barrier system.
I worked out how to get the trim off (yes it just pops off using a paint scrapper) but then it fouled on the cargo barrier.
I investigated how to get the wire outside under the body or though the chassis rails. That became too difficult so I have just threaded it back under trim and above the carpet and then about halfway along and under the rear carpet trim. .
I had to make up an extension using some small co-ax cable and some SMA connectors
The TPMS now seems to pick up the signal from the trailer wheels more consistently but the proof will be when we do a longer trip.
Trevor