some venues allow you to take pictures---some do not- be sure to ask at the table when you pay to enter.
remember you are not allowed to touch the quilts- there will be (workers) around wearing white gloves = who will lift a corner for you if you want to see the back of a quilt.
wear good, comfortable walking shoes- plan on doing alot of walking- once in a while you will find a show that has chairs, benches placed here & there for you to take a rest---others do not include that-
as for what could be available-
everything quilting related- from patterns, kits, fabrics, notions- machines- sometimes there will be classes/demonstrations going on- frames set up to see/try hand quilting, long arms set up to try out-
all depends on how large the show is....many have drawings, raffles, silent auctions. it is so great to visit shows! have fun!!!