Several things you might want to check...
1) Sealant condition on the edge molding along the kitchen side of the trailer (IMHO, long shot)
2) Sealant around the porch light...sounds strange, but, that light is directly in line with the sink on the 189FBS. If it is leaking down the inside of the outside wall and the tilt is towards the other side (street side), it may be hitting the floor and running to the front of the sink area under the linoleum. A hard driving rain may not produce the leak as the rolled up awning may offer some "shielding", while a gentle rain with some breeze may be constant enough to cause the issue.
3) I'm not sure where your vent stack is, but, it is possible that you may have a leak around the base where it sticks out of the roof. Usually there are two vent stacks...one for the black tank (located near the bathroom and its black tank) and another for the gray water tank, usually located more forward and in your case, probably near the kitchen.
Just some more places to look