JT,

It is technically possible to do it by bus, but it involves multiple buses and takes close to an hour & a half. Not sure just what times you're talking about either, so your best bet is to use their trip planner located here.

For your origin, choose the landmark tab and then on the drop down select Colonie for the city. Then choose Travel on the next drop down, followed by Albany airport. For Destination, choose landmark; Rensselear; travel; Amtrak. Then pick you desired travel time for which buses to take.