A bit tough to state specifics because it is not something we can see, when we speak of radio waves! So I fall back to general ideas and then f it is practical, I like to install the repeater with some form of temporary wiring setup to make sure the spot I have chosen works well.
When I gamble, I tend to may small bets until tested! But there are ways to increase the odds of being right if we use some ideas of how the signals might best work.
The sensors are not of the sort of antenna that sends a signal in a specific direction but I think of them as being more like a fireworks sparkler? Sparks fly out in all directions, up, down, left and right, even though we can see the radio waves! Things that stop them are metal as worst, with heavy or thick materials as less problem.
Planning says that the dash is often pretty open for a long space toward the back. Setting the head unit up a bit like the top of the dash can be better than down lower where the signal has to get around the chairs, etc.
If we can imagine a straight clear path from the head end to the repeater, that is often looking down the center aisle and often not hard to imagine a signal going there will little problem? If we look from the head end to the repeater, it may be easy enough to see a pretty clear path! Often it helps when we put them both a bit higher, as we have all the other things like stove, frig, water heater, down lower? No need to shoot through the booth seats or other if we can get it above them!
But it has to be both the signal from the repeater to the head but also we have to put the repeater where it gets the signal from ALL the tires and that can to harder as there are lots more metal getting from the toad wheels and that is not one we can change, so I tend to think putting the repeater farther back in the RV. The trip from repeater to front is often something we can arrange to be open far more than the toad to repeater.
That can be where I like to play some games to see what works before making it permanent. Can you see a way to do a practical job of temporary wiring for testing? It takes a combo of ease of wiring and also practical to have a sensor hanging out in the way if in the wrong spot!
Suggestions are my "first guess" and I actually do not have major trouble getting to to work. The TST line is one I have used in several different RV and not been a major problem. Does that mean they are good or have I been lucky???
Check if this first guess seems to have the more open path, generally more equal for getting signals from car to repeater as from rear wheels to repeater.
I think I spot a couple 12 v ports that might be handy to put a plug on the repeater wiring for testing a location? Or is there a semi-handy point to get power to it? It doesn't need much and there charge ports might be a handy one to look at as they seem to let you get it higher and also that might help get it out of the way?
Part of the thought it that they are less likely to be used for charging the cell phones, etc. while driving and they might already be set with fuses, etc. to be nice if you could just tap into them??
The repeater is really low power user and even then these will be connected to the engine alternator as you drive, so no problem drawing down batteries.
Blue for power source and red as possible locations for repeater?
This might put the repeater much closer to the toad which is automatically further but also put it somewhat near the rear wheels which tend to be in a more "metal cluttered" spot. If you can almost see an open shot back to front, this might be one I would try as it tends to favor the harder things to get from wheels to repeater!
A location along the back wall might be good but getting power may be harder?
WARNING!
Sometimes my theory is totally defeated by real life, so I have to test before trusting!
Wish you luck and that seems to be good in lots of things!
