Nevadastars,
You have been given some good advice and, some diagrams that may work just fine for you. I would like to offer another alternative if I may. Now, you say in your original write up that, you have "separate running and signals lights" correct? I'm assuming you mean, you have a running light, a brake light and, an "amber" turn signal on the back of your toad, correct?
If your coach is a "two filament" system, that is, a running light and, a "combo" brake and turn light, (no amber turn signals), then yes, IF you want your toad lights to be wired in such a manor that the lights on the toad act exactly the same towing it, as they do driving it, then yes, you will need a "tail light converter". And, like Mr. enblethen suggests, you will need the "two wire to three wire converter. They are simple to install and serve a very specific purpose. They will allow for a "combo" system, like what's on your coach, to activate a non-combo system, like what's on your toad.
Those little boxes are amazing. But, they work and, that's all you care about. I'm going to send along, another wiring diagram that I drew up just after wiring one of our recent toads, a 2011 Honda CRV. You'll have another choice in the way you can wire it. The diodes I used are not the expensive ones from Camping World or any RV supply outlet. I used some from Radio Shack, a three pack for about $2.89. A diode is a diode so, you an pay a lot or, not much at all.
On our CRV, it has the "three filament system" with amber turn signals and, when towing it, and the lights are activated, it looks just like it does when driving it.
Scott
