You said some very powerful things - in your post.
First of all - you need to understand - that you have a deep connection with your past. You feel comfort in your past. Your soul gravitates to the memories of your past - those that were pleasant - I suppose.
Second - you see your progression into your future. You accept the growth and transition. However - there is apart of you that is 'amazed' at how far you have come. You are amazed at the success you have achieved - as you are comparing it to the 'Biltmore' house. The image of this house represents some level of prominence and wealth - that you have received - as a result of your efforts.
Lastly - you stated that the third floor of the house was closed - but - when you returned to it in your dream it was open. This suggest levels of success in your life that you have obtained - that were once - out of reach for you - but have now become reality.
The most recurring theme in many of my dreams are fishing (rivers and lakes not oceans). When fishing, I rarely catch anything, just the process of fishing. I also dream in color, sound, and temperature.
The answer: This dream speaks of 'opportunity' - and - your perception of it. You see yourself as having moderate opportunities - however - you have not considered yourself to be fortunate enough to catch anything of significant value - through the opportunity.