What Tom Tom fitting kit have you got? I recently fitted a Rider 400 with the supplied bar mounting kit. This is the type where the cables go to the mount and the Unit can be removed, refitted from the mount without connecting the cables.
I used to use a plug in "cigar lighter socket" connection on my last bike but found that the plug would back out when riding, losing connection. To get a "hard wired" tidy job on the Tracer you can use the vacant wiring plug for the optional second power point. This also has the advantage of being fused and switched off with the ignition (useful if you have the locking kit or leave the Tom Tom on the bike when garaged.)
You can find the block connector under the front panels. From memory is below the windscreen on the Left hand side (riders view). I removed the screen and I think the body colour panel near the headlights. Find the block connector for the standard power socket and the spare connector is next to it. I fitted a new male + female block connector as I had nothing in my kit to match the original. I then ran the wire under the headlamp, zip tied to keep it secure and made a small hole in the spare power point blanking plug. Form here the cable can be zip tied to handlebar cables and wiring up to the mount. My kit had a quick release in the last few cm of wire, in case you want to remove the mount bit you could achieve the same thing with a waterproof in line fuse holder.
Hope this helps!