Do as much research as you can prior to going. Functionality is often overlooked. Imagine cooking a meal, taking a shower or what an be done indoors with 3 straight days of rain. Many kitchens have limited counter space.Many couches are NOT comfortable.
Figure your price point.
You will see LOTS of bells and whistles. Suggest you concentrate on what you will truly use the most. Theatre seats vs couch. Bed sizes in RVs are usually a bit smaller.
A pretty RV is wonderful but over time, a livable RV matters more.