I hate water leaks. Had to deal with many on my 06 Keystone before upgrading to a new White Hawk in May 2013. One thing I've learned is the cause is more often not that obvious. The fact that it occurs after rain and you don't have the problem during hot humid weather pretty much indicates it NOT condensation. Water from outside is affected both by gravity and wind. It comes in thru cracks or penetrations but not necessarily directly above where the water is pooling. It can come in and travel along a roof support before dripping out of a light fixture. Usually there is a lite over the table so I would check that out. Also put a towel on top of the table after drying everything up. After the next rain [or make your own rain with a sprinkler] and it will be easier to see exactly where the drip is coming from. If the table is not exactly level, the water will run downhill on the table and the towel will prevent that.
If I had to place a bet, I'd check out the light. Water will typically not just soak thru a ceiling. If it rains and there is a drip, its getting in thru an opening or seam. Since you're saying there is no sign of wetness on the ceiling, I'd go with the light. That still doesn't mean that's where it coming thru the roof. Your problem is going to ultimately be somewhere on the roof or where the roof meets the trailer side wall. To isolate the leak, you can run your hose carefully on the edge of the roof on the side where your table sits. Run a gentle stream for a few minutes and watch the inside. If nothing, then run that same stream carefully around each opening [roof vent, plumbing vent, etc] one at a time. Give each location time for a leak to make it inside. Remember water will travel and not necessarily show up directly underneath where it is leaking. Be patient. And don't worry the little water that you get from your testing will not cause any permanent damage at least in comparison to what an ongoing leak would do. If it is happening everytime it rains, your testing with the hose will likely direct you to the problem. Solution will be easy once you find it. Don't use sylicon or regular household caulking. Get something at your RV service center that is designed for RV's.
PS; Is the table on or under a slide? I had a leak on the parameter of my slide at the tip where it had not been properly caulked causing water to pool on a window ledge inside. First thought it was a window leak but NOT.