A great natural sweetener is Date Sugar. It's pricey at $6/lb, but it registers very low on the glycemic index and is considered safe for diabetics. It does NOT give food a date flavor, and is sweeter than sugar so I use 3/4 cup for every one cup sugar.
For flour I use Tom Sawyer GF flour... www.glutenfreeflour.com
It already has Xanathan Gum, so there is no need to add it. I actually really like this stuff, it can be subbed cup for cup with regular flour.
I made Blueberry muffins with these two things last week and they were delish!