Hey there Hydalique!
Parts are still available for most any road bike. The parts interchange from manufacture to manufacture. Tire sizes vary, but the 27" tire is a popular size even today. I do my own work on the Schwinns, but any bike shop could perform the same services that I am doing. You should get those classic Schwinns out and have them tuned up,bearings repacked, replace the tires and tubes and hit the road. You will be shocked at the things that you will see, that you miss out on when you are driving a car.
Don't worry Vulcanchef, we will catch up to your $6.24 per gallon within a month or two. Don't forget, we have the oil companies in charge of the White House here in the USA. The GOP is the party of low taxes for the super rich, and BIG OIL for themselves.