First, I am not great at home improvement projects, but on our old diesel pusher, I replaced a 19" bedroom tv with a 25" Vizio and it was very easy to do. On our new Via, I have replaced the 12V Jensen******tv with another Vizio. So my message is, the same as mdprince, do it yourself. Either put the new tv in the old tv space, or find somewhere else for it. Our diesel pusher also had a roof mounted satellite dish, and in 2011 it cost me over $300 to get it up to standard to pick up Dish tv. Traveler is a good option for satellite, and you can pay Dish on a monthly basis when you need it without a contract. Look at Dishformyrv.com.
Dish for My RV. There is a lot of good information on the website. The hardest part of the job is going to be getting the old tv out and disposing of it.