If you can't find space in the hotels, maybe try The Stink? I was able to get in random games at that last year. If that's not available, check to see if the cellar at Union Station is open. They've had Drunken D&D down there in years past. Not sure if they still do that or not, but it's a pretty cool little pub with tables/booths and a dungeon/tavern vibe.
If you don't mind a bit of a walk and the weather is nice, there are two new park areas at Washington/Alabama that have tables. The one on the Northeast corner of that intersection has a great big table, kind of tucked away in a grassy area.