Welcome to the Forums and greetings from a '64 Overlander owner!
Land Yacht that you will be looking at is likely a Trade Wind given the length of 23'. According to the Airstream corporate site, this trailer would have an empty weight of 3,500 pounds and a tongue weight of 415 pounds - - both of these are empty weights and do not reflect the weight of any optional equipment, fluids (water, propane, etc.), or personal posessions. It would not be uncommon to add between 700 and 1,000 pounds to the empty weight to arrive at the actual loaded towing weight. See the link below for the Airstream weights and measures pdf:
Airstream Weights and Measures
The current owner says the Air Con was a retro fit, and currently doesn't work. She felt confident that a new one could be easily found, any comments from anyone?
If the air conditioner is anything other than an Armstrong Bay Breeze air conditioner, it is likely a retrofit/aftermarket installation. The greatest hazard is whether the installer was familiar with Airstreams - - someone not familiar with Airstream MAY have installed the air conditioner unit in an existing vent opening which usually isn't the intended location so likely wouldn't have been properly braced. So long as the existing air conditioner is properly located, installing a modern replacement isn't a particularly difficult operation - - if it is an Armstrong Bay Breeze, a 14" square opening will need to be cut in both roof and ceiling panels as the Bay Breeze used three small round holes rather than one large square opening.
Also, she felt the Land Yacht only weighed 3000 lbs. We had been considering a new Bambi, and I understand they weigh 3770 lbs, even though its only 19ft vs this used 23ft, anyone know why the difference?
There are a number of reasons for the differences in weight between the 1960s coaches and the current coaches - - especially the classics. Some of the differences include:
1.) Countertops and table tops were formica laminate over a "light-weight" substrate rather than the Corian that is used in many of the new coaches.
2.) Floor coverings were either 9" square vinyl tile or sculptured carpet (at least in '64) - - rather than pergo and some of the heavier floor covering products in current use.
3.) Cabinetry was a cabinet grade of veneered plywood rather than some of the hardwoods used in today's coaches.
4.) Some equipment that is now standard was optional then. For instance, according to my notes, the Univolt did not become standard until 1964
5.) Vintage coaches only had one wastewater holding tank for blackwater (ranging from 8 to 12 gallons depedning upon model). Water tanks in the Vintage coaches also were usually under 30 gallons - - but this was not necessarily a weight savings as prior to 1964
the system was usually a pressurized system that required a galvanized water tank rather than a plastic unit.
6,) The foam used in the upholstered goods in the trailers seemed to be of a lighter, less dense material than that used in current trailers.
7.) The Vintage (pre-1966) coach windows were plain household window glass, and not the tempered glass used in the newer coaches
While you didn't ask, some things that you might want to know about the early 60s Trade Winds:
1.) There were two basic floor plans. Center Twin or Center Double; both would share similar rear bathrooms (if memory serves correct with a tub/shower combination), the kitchen would be located immediately ahead of the bedroom are, and the living room would be in the front consisting of a single lounge. If you are fortunate, the trailer will include its original drop-leaf table and chair(s).
<<The center twin will have a twin bed on either side of the aisle while the center double will have a dresser wardrobe arrangement on one wall (usually curbside) and a pull-out double-lounge on the opposite wall (usually streetside).>>
2.) The trailer may be a single or a tandem axle. The single axle was the standard arrangment, but a tandem axle was optional until 1964
when the double axle was said to have become standard. If the coach has tandem axles, it may or may not have brakes on both axles as my notes indicate that the brakes on the second axle were optional as well.
3.) In the rear one-stop service compartment, you will find all utilities including the Univolt if so equipped. The battery is also usually found in this area next to the bathtub/shower unit - - if my '64 Overlander is any indicator this is an area that needs to be checked as the tethers broke on the battery and it did a dance in the rear compartment damaging much of the bathroom plumbing at some point before I purchased the coach.
4.) The operators for the windows are (or at least were as late as 14-months ago) still available for these coaches, but the installed cost approached $50.00 per operator. It pays to check each window for operation and condition as it doesn't take too long to invest a $100 or more per window in repairs.
5.) If you find yourself becoming serious about the coach, you will want to be sure that all systems are operational. Even if all are operational, it is best to be prepared for a replacement cycle to begin as many of the systems will need replacement or upgrading - - for instance, on my '64 all systems have needed to be upgraded since 1995 including furnace, water heater, air conditioner, refrigerator, water pump, water tank, Univolt, electric service panel, water filter, and all water supply faucets.
6.) The coach may also have its original split-rim wheels that were considered premium trailer wheels in their day. Today, many, if not most, tire stores nearly refuse to work on such wheels so it may need rims as well as tires to bring it up to current travel standards. Brakes are another issue as the originals would be of the "oval" design that while functional is now obsolete meaning that the parts aren't always readily available - - the usual solution (applied on my '64) is to replace the backing plates with modern "fully-loaded" backing plates that have all new modern brake parts (the only additional expense was turing the drums and machining the shoes to match the drums).
Please don't interpret this information as discouragement. I truly love my '64 Overlander and wouldn't consider trading it for a newer coach. Since you have been primarly considering new, I just wanted you to be aware of some of the issues that we Vintage owner's face with these wonderful old coaches.
Good luck with your inspection!
P.S.: You might want to consult the following link to learn more about the trailer by its serial number (VIN).
Pre-1980 Airstream Serial Number Decoding
The serial number should be on a plate to the right of the entry droos along with another plate (possibly on the same plate - it varied by year) that identifies the series.