Hello, Alex, and Welcome Aboard!
The newer Athearn RTR engines and cars are very good values for the price. The bay window caboose is a model of an SP prototype and, although it's a good loking model, you might want to check out Walthers RTR Platinum line of Bay window cabooses. They are International Car Company prototypes and were much more common than the Athearn model. Don't overlook the Bachmann Spectrum line of locomotives. They are also very nicely detailed and good bang for the buck.
There really isn't any track and roadbed system that looks realistic. As Alex said, the Kato Uni-Track is the best operating of the track systems but you're going to pay through the nose. Assuming you intend to build a layout, you can get a lot more for your money by using Atlas Code 83 track and either cork or foam roadbed. The Atlas track comes with good looking brown ties and you can buy it with the track preweathered. The only thing you have to do is ballast, which may appear daunting at first, but is really not difficult. Your track will look much better doing it this way than buying any track system.