Ask at your local sew store or LQS. They may let you use their back room/teaching room to pin. Take your stuff there, push two or more of their large 8 foot tables together and pin on that. My local sew store even has 'plastic booties' (sawn off pieces of pvc pipe) that fit onto the legs of the tables to raise the surface up to comfortable height of 34" to 36".
I roll out the layers... baste pin, move the quilt, smooth... baste pin the rest. Then carefully look it all over for puckers, creases, sags etc. adjust if/as necessary. Then put all the pins in it, use the binder clips on the edges. Then roll it up and take it home. Sometimes, I bring the shop owner/workers lunch and my sew machine. Then I pin before lunch.... we all eat lunch together and chat...then I continue to use their room for quilting the large quilt. It's MUCH easier than trying to do it at home. I'll spend the day there. But I'll stop and talk with whomever wanders by. It helps that I will talk to them about the machines being sold there, about the service and how good they are <wink>. It's true, plus I act as an unpaid marketing person for them. And they let me sew... it's great!