These are a few of my favorite vintage folding/compact finds:
vintage metal folding desk
vintage suitcase/folding table
This one comes from my personal collection, and is perfect for picnics! The faux red snakeskin is pretty fun too.
vintage compact table and camping chairs
The table folds up suitcase size with the chairs inside, locks & has a handle so that you can take it anywhere you want to go!
vintage Ritec folding picnic/camping table and bench chairs
I was with my friend when she stumbled upon one of these in a thrift store and we freaked out about how small the table AND benches could fold up to make a portable picnic table. (It isn't light, though, so you won't want to haul it too far).