The pictured Airstream is a 1961
22' Spaceliner built in the California factory in October 1960
. The Spaceliner is a fairly rare model only made in 1961
(plus a couple of prototypes at the tail end of the 1960
model year) with just less than 100 total ever built. That said, I don't suggest that the rareness of this model adds significantly to it's value.
The Spaceliner was sort of a unique floor plan in that is had the furnace located on the front wall of the trailer behind the propane bottles and between two long front dinette benches that also served as twin beds. It also had a second "L-shaped" seat/dinette behind the door that I believe originally had a free standing table.
The Spaceliner was one of several different 22' floor plans offered in 1961
, so 22' 1961 Airstreams are pretty common. Other 22' floor plans included the Flying Cloud, Safari Double Bed, and Safari Twin.
The Spaceliner was only built in the California factory and has a "TD" un the middle of the serial number, while the Safari Double had just a "D" and the Safari Twin and Flying Cloud both had just a "T". The Ohio serial number formats were totally different
The Spaceliner is often confused with the Safari Twin, which also had long front dinette benches, but a different furnace location and straight gaucho rather than L-shaped bench in the middle. The serial number makes it clear they are different models.
This Spaceliner looks to have already been renovated, keeping the original floor plan for the most part, but changing several things. The curved aluminum cabinet holding the round sink is a modern addition that seeks to mimic a design detail on some current Airstream models. The portions of exposed aluminum skin on the inside were also added to mimic modern Airstreams. The interior skin would have originally been painted with a speckled paint called zolatone. All of the cabinets appear to have been refaced with new wood. The hanging microwave cabinet and the wood slats added to the inner skin above the L-shaped dinette are modern additions, too.
It appears that all propane appliances have been removed (fridge, stove, water heater, and furnace) and a modern "mini-split" air conditioner/heat pump and electric fridge added. There is no stove at all. This means the Airstream is now "electric only", which might or might not work depending upon your intended usage. In RV parks, it would work fine. Boondocking (i.e. camping where there are no hookups) would only be possible if you bring along a sizable (and hopefully quiet) generator.
We cannot also tell from the photos if there were holding tanks (fresh, gray, and balck) retained or added during the renovation. They could have been deleted if the intent was to always use the trailer in theie back yard or in RV parks. A lack of holding tanks would also make boondocking very hard.
Overall it looks to be in nice, usable condition. Of course, photos cannot tell if there are leaks or if all of the systems work. These items and the presence of holding tanks would have to be checked out in person.