Welcome from Colorado: You are wise to look for a used trailer as they usually have the bugs worked out of them and will cost less than new. But the market is on fire, so don't be discouraged at pricing. Airstreams do hold their value well.
If you plan on full time travel for a year, consider a longer Airstream with more room in it. It will have a larger fridge, more closet space, and a larger bathroom which makes travel life a bit more comfortable. We have a 1986 Limited 34'. It is long, but it handles well and I just backed it into a campsite between big trees. If I can, I'm sure you can. Airstream trailers last a very long time.
Look in the classified section of these Forums and search there for used trailers. Click on the Classifieds on the top of the page. There are other sources, but Airstream Forums is where the enthusiasts seem to gather.
WBCCI #8607 VAC Region 11
KnowledgeBase trailer renovation threads: 69 Globetrotter, 76 Sovereign, 75 Overlander, 66 Trade Wind Such fun !