You are doing a great job!! Isn't this a fun quilt? I love it that you are doing the 6" blocks--the pieces were just too tiny for me. The wagon wheel is not hard at all--I actually hand appliqued mine and I don't like to applique at all--you will do just fine.
And don't worry about your blocks not looking like they belong together-that is just the nature of a sampler--it will look great when you are all finished. Keep 'em coming. :-)