I think you're near the "happy hunting grounds" for Airstreams. A lot of retirees park em in Florida... then either pass on or need to go into a care facility. Look on craigslist and newspapers in Florida.
With two small children you may not want a "spare time hobby", so consider that the older your unit, the more likely you'll have rehab, replacement and repair issues. You might pay a bit more for a 90's unit, but you'll get a newer furnace, refrigerator, air conditioner, etc.
It surprises me how low the prices can be on larger 90's units - and with 4 people unless you're planning just weekend and short hop camping trips, you'll probably be happier in a biggun!