3 pieces of COAX are an excellent way of doing things. RG-6 is an excellent video conductor and is far superior to most store bought cables for its ability to reject unwanted noise.
The weak point is definitely the F to RCA converter, but I would say that the quality of RG-6 outweighs this failing.
You can look online though and get RCA termination cables that go directly onto RG-6 cable. It may be a little pricey for the compression tool and first batch of terminators. But, you will have that tool for the rest of your life and can make custom cables on your own exactly how long you want them. Great way of doing things.
Or, you can live with the converters and be totally happy with them and really not see a difference in your image quality. I never had a problem with the converters.