I have layered quilts on tables in my church fellowship hall and at the library where my guild meets. Look for some open to the public" type buildings that have banquet tables. Push two tables together or maybe three if your piece is large, and you can walk around your layering process whether you pin or spray baste.
For smaller quilts, I layer my quilts on my quilt wall, I do protect the edges and the floor with wax paper or other scrap paper to protect my wall and floor from over spray.