I would use one larger sized unit as opposed to daisy chaining. The better units will have a solid buffering and line amp on each output as opposed to simply a resistive bridge between the output jacks.
The big box stores are famous for selling distribution amps with only a 75 ohm series resistor tying each output to a common output buss. This is a big problem. The reason is that each termination device (display) has its own built-in load resistor so without active buffering you would get a substantially reduced voltage to each unit. The other issue is reflections and ringing in the lines of differing lengths. That is usually not an issue with separate buffered line drivers.
Look into Extron and Kramer for top quality gear. They both have dealers all over the country.
If you opt to run RGBHV, I would strongly suggest Canare V53C-5 conductor jacketed coax. Super flexible and excellent specs. It is the pro industry standard. It does use only Canare BNCs due to a slightly smaller diameter than other brands, but it is worth the money, IMO. You can find this cable and the BNCs and the crimp tool at most industrial electronics supply houses.
If you opt for VGA, Kramer, QVS and ATEN have great quality and reasonably priced, larger scale DAs, and you can get excellent grade VGA cables in stock lengths up to 100 ft and very reasonably priced from QVS (NOT QVC)