i've done one quilt with just the top and the fleece, and another with top, batting, and fleece.
when i didn't put anything between the top and the fleece, even with a walking foot, i had a bit of an issue with distortion on the top because it didn't stick to the fleece. i had to pin the heck outta the sucker.
if you don't want to use batting, i'd recommend you put a layer of prewashed cotton flannel between the top and the fleece. the flannel will stick to the fabric because they're both cotton. the flannel will also stick to the fleece because they're both fuzzy. it will make quilting them much easier.