Is there long term parking available at Albany-Rensselaer station? I would like to leave my car there for 2 days.

Short answer, yes. It costs more for the garage I believe. Outside parking is less.

I found some dated Info: Rensselaer Rail Station Parking ( Effective April 1, 2013) First hour FREE. Each Additional Hour: $2.00 Garage – daily rate $12.00; 7 day rate: $50.00 Surface Lot A – daily rate $8.00; 7 day rate: $35.00 Surface Lot B – daily rate $7.00; 7 day rate: $30.00 Surface Lot C – daily rate $8.00; 7 day rate: $35.00 Customers with disabilities – half rate for Parking Garage