I just installed the Wilson trucker cradle amplifier about a month ago, and it is working very well for us. The antenna is mounted about midway back on the curb side of the coach, where I drilled a hold just under the drip rail to run the coax into the overhead cabinetry. This made it easy to hide the coax and get it over to my monitoring panel. I then drilled a hole in the panel and mounted the cradle there. The antenna is about 8-9 feet away from the cradle and that seems to be plenty, no problems with signal or feedback. I also installed a cigarette-style outlet inside the power panel so I could plug in the amplifier without modifying the end, although you could easily hard-wire it if you prefer.
We leave our MiFi device in the cradle and run a short usb cable from the amplifier to the MiFi to power it, which reduces wiring, and we have it powered all the time. We located the cradle where it's easy to remove the MiFi and put a cell phone into it if it needs a boost. We really see the signal bars come up, although of course we have to put the phone on speaker to use it that way. There is a photo of our cradle setup here:
Southern Sojourn -Gulf Shores, AL | The Lowe's RV adventures
I guess the bottom line is that you probably don't have to run the coax all the way back to get the separation you need. One side of your RV should have enough cabinetry and distance to make the coax installation easy. Inside the ceiling can be very difficult, since much of the wiring there is just stuffed in with the foam insulation - I haven't seen any channels for wiring but it would sure be nice if they'd provide one. You could run quality coax on top of your roof, although I understand if you hate that idea as much as I do. But it really doesn't look that bad if you strap it down nicely.