Not much going on rail-wise on a Monday, but there is no admission fee for Steamtown and it's still worth exploring the roundhouse and grounds for a couple hours. There are plenty of picnic benches if the weather is nice on the day of your visit.
I highly recommend the Lackawanna County Coal Mine Tour - it's affordable and a really unique experience. The tour itself takes about an hour and the mine stays at 53 degrees all year, making for a nice break on a hot July day.
There are plenty of nearby restaurants, depending on what you are looking for. The Radisson, which was already mentioned, is a popular spot, as well as Cooper's Seafood House.