Check the back of your present audio system and notice what type of input jack is being used. Most likely it will be RCA Audio plugs. Those red and white ones, and yellow for a video input. Now look at the television you are going to purchase. What is the "line output" on the television, sometimes just labeled "audio out." I will venture to say that most of the newer flat screen televisions are missing the RCA Out jacks and instead are using the TOS (optical) output, or Coaxial output.
If the television audio output is not compatible with the audio input of your stereo system you will not have all your speakers working and will have to rely on the television speakers. Or, you can look for a television that meets your audio system requirements. Or, you can replace the audio system.
That is what I am going to do, replace the audio system. We never use the am/fm feature of the audio system. So a good receiver with a DVD player (fancy of course) with the necessary audio inputs is what I'll be looking for.
Also, looking at televisions consider if it is going to sit in a present hole or be able to be extended. If it is in a present hole then you want the television speakers on the outside edge of the television. This will decrease the screen size that you can have by having the speakers underneath or on the insides. I went from a 30" digital ready on my 2008, to a 36" tv. The outside width was 36 inches and I have it mounted on a swivel mount. When traveling it fits into the original hole. When we are watching it, I pull it out 3 or 4 inches so the speakers are outside the hole.
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2015 Winnebago Tour 42QD 2008 Winnebago Destination 39W
(RVM-14) It is what it is, and then it is what you make of it.