Some quick thoughts:
1. Don't get so involved in the re-do that you forget to ENJOY the RV.  This might make more sense in Spring!
2. Before you build a new altar for the TV, decide if you will actually use it. We have watched TV maybe four hours in 10 months in the RV.  We removed the bedroom TV and built a bookshelf.   I would remove the living room TV if it would not leave a big hole.
3.  Decide if your ideal layout is plausible.  If not, you might be ready to trade for a more suitable one, before you empty your wallet.
4.  If you love the process and will like the result, don't get too concerned about the cost.  Street rodders have been building cars and losing money on them for decades.
5.  Consider Ikea as a source of furniture - small frame, contemporary look.  Bolt it down unless you want it hitting the back of your head in an emergency.
6.  A dog is a very important RV accessory!
Matt B