Looks like a material problem, but I can't find anything to remove? Really sorry as I'm a beginner and I don't know enough to characterize, or accurately search for what the problem may be. I've taken a picture of what I'm seeing, where it appears the faces have different textures, but nothing shows up under materials, and it's currently causing the solidify modifier to thicken differently along the edges and inside the areas. 

I appreciate any help you all may give!
When you solidify, make sure that ALL the faces are selected. Judging by your picture, it seems that you did not do this.  If I am incorrect, please upload your .blend file, and I'll see what I can do.