Dave,
Let's play with the Math...
You have a 750 pound limit for your bunk; but only a 300 pound limit for the ladder...
It sounds like two buck-naked 300 pound people could climb up; after they've tossed 150 pounds worth of clothing, bedding, and evening snacks up first!
( I'm NOT saying that you and your beloved weigh that much... this is just for illustrative purposes.: whistling