Need help figuring out value for painting or whatever it is [View all]

My mother purchased this very large matted,signed painting at a yard sale back in the early 80's. She also purchased a bedroom set from the same people I have since sold which was very high quality. I had introduced my mom to yard sales late in her life and oh my god how she took to it! She would call me every weekend with her "finds" proud as can be. It was so cute! I had created a mini monster!

My mother is since deceased and now I have it. Yes, it is lovely, but I need to downsize and I believe it is too large for the space I am moving to. Framed, it is about 44"wide by 36" high.
Anyway, it is a huge framed and signed painting(?), watercolor(?) of a southwestern landscape at sunset signed by Gaylor or Taylor.

I can tell it is not an oil painting but I am a novice when it comes to art. How do I begin to determine a value and how can I tell if it is a watercolor or whatever?
Yard sales in my neighborhood yield people who want to pay 5$ or less for your entire lot.

Good grief I feel stupid.