Deanna,
Some quilting friends of mine went to Walmart and got rolling toolboxes to keep all their stuff that they take to classes and retreats. I'm seriously considering doing the same. Something of that nature would work for you, I'm sure. BTW, they all have the SewEzi tables for their machines too. I was so impressed with them, that I ordered one for myself. Just arrived yesterday, and I'm so pleased. Most classes and retreats provide tables, but with the SewEzi inserts, you have a flat sewing surface. A set-up like that might allow you to sew, while still having your patio table free for cutting fabric, etc.
Have a great day!