No, the "toner" will not accomplish the task you are trying to do. As noted, it is an audible tone device used to identify twisted pairs for phone and internet connections. It does not emit a frequency that can be picked up by an external/distant (not connected) listening device.
As for your tracing your existing wiring, lots of luck. I have tried to follow the wiring on our 03 Beaver Patriot and cannot find the coax that goes from the overhead location to either the bedroom connection or the hookup connection in our water compartment. I have gone so far as to trace them across the front and down the trim piece on the left-hand side of the windshield. From there they must run along one of the chassis rails since I too have an outlet in my lower bay. I suspect this is the route anyone at Camping World would follow to install a HDMI cable per your request. And, after having removed the trim piece myself I can tell you that you have to remove the wood piece that hold the windshield visor to have room to remove that part. I only mention this because at the typical rates of $110 per hour this can really add up fast.
It would be helpful to know what kind of receiver you have in the bedroom. Since you have already run an HDMI cable to it, it sounds like you already have a flat screen TV there. If so, your wiring is probably good enough to support the suggestion by PokerJoker of sticking a H25 back there behind the TV and use RF on the remote. This would be far simpler than trying to run a HDMI wire. I would imagine that the HDMI wiring would be 6 to 8 hours to run it from the front TV area to your bedroom. You will just need to add another splitter between your frontroom receiver and the coax that goes to the bedroom TV.
Our coach's sound similar. You are right on already upgrading the TV's to flat screens. On the new HDMI runs, I only "Tested" the HDMI's by loosely laying them out in the aisle way as a means og testing signal strength & quality for that distance (40 feet). No problems on Strength & Quality for 40 feet HDMI cable.
The new Winegard SKM SWM3 is an open array, self aiming true SWM antenna that is installed on the roof. And based upon some of the discussions here, I come up with another idea that uses the existing RG6 cabling that routes to the Bedroom and Basement/Service bay. I already know that cabling "works." As I understand from 2 different Safari Yahoo websites, the RG6 Cabling starts in the entertainment cabinet and splits behind one one the cabinet walls. If that is true, then the solution would be to disconnect both RG6 cables from the splitter, connects them up to the SWM Switch and relocate the receivers (D-12-100 to the basement & a H25 behind the Bedroom TV) as someone above suggested. I also have an HR20 DVR for the main upfront TV (last model to have an external OTA Coax connector - RV Parks cable systems and my Batwing/Jack antenna connectors).
So I'm off to to the motorhome searching for a splitter and hoping it is in fact hiding behind a cabinet up front. Just in case it is up front, I'm thinking that I may have to "Extend" the length a couple of feet each to reach the SWM Switch. Could I use a Barrel connector and a 2 - 3 feet long second RG6 cable as a means of extending the reach???