I'm flying IND-MSP-DCA this Sunday (cheapest fare at time of booking). I originally had a 3ish hour layover but a schedule change has pushed that to almost 5. I have Amex Plat so I can hangout in a Sky Club or the Escape Lounge, but I've never been to the Mall of America and wonder if that's a worthwhile excursion?

Is the light rail pretty frequent/reliable between the airport and the mall? Is 4.75 hours enough time to make a comfortable trip there?

Any suggestions or tips are most appreciated. Thanks!