When my friend got her long arm she started practicing by buying quilt tops on ebay or thrift shops ... some of the areas of the quilt she wrote her name over and over, another section she did loop de loops, and on and on till it was done. Was it pretty, no not really but she had lots of fun, playing, practicing and learning how she and the machine worked together. When it was done the quilts turned into dog beds. Now she is an accomplished quilter!
So do as someone else suggested, just put some sandwiched muslin on your machine and have fun quilting.
Truthfully, I wish I had a long arm machine, but I want to quilt on it (after having played on my friends several years ago, boy that was fun) BUT doing the setup is what hinders me from even thinking about getting one, LOL... you have already got that down. Hey invite me over and we can play together! Oh dang you live too far away!