Welcome to Airstream, and the thoughts of ownership of the 2000 LY.
Go here for an Owners manual http://www.airstream.com/airstream/p...AS%20Parts.pdf
The frame of your motorhome will not be a problem. Depending on your past experience, you may enjoy driving this chassis, you may not. It has been known to have steering characteristics that some find objectionable. Others don't. There are aftermarket kits sold to address this. Newer, better shocks are available. Depending on your right foot, the engine can give service between 50,000 and 80,000 miles. Due to the hardworking environment of a motorhome chassis, and the fact most owners stick the accelerator on the floor, demanding a great deal from these engines, they normally do not give extended service, even when maintained on short intervals. It shouldn't be looked at as a faulty or defective engine, but rather as the normal service life. It would be like putting the smallest economy engine into a large limo and expecting it to produce for 100,000 miles without a problem, all the while having the accelerator planted on the floor.
As stated before, you have 2 distinct systems here that you, the owner, must keep up with. The RV, and the chassis. Tires normally will be changed as a result of a)failure due to lack of air pressure, or b) getting old and degrading. Very few MH's use up the tread. Brakes last close to the lifetime of the unit, unless you drive with your foot on the brake. MPG's will be 6 to 7.
Battery knowledge is almost imperitive. If you don't educate yourself on them, expect to buy new ones often. If you do educate yourself, plan on monthly maintenance, however, that takes very little time.
If your unit has a convection oven in it, do not drive with the rotating dish inside. If you do, expect to spend $75 for a new one!
Transmission coolers are the saving grace for this chassis. If it doesn't have one on it, install a LARGE one immediately. If it has a small one, install a LARGE one immediately. Nominal cost, huge benefits.
I'm not trying to scare you away, as I drive a MH as well. It's just too many people don't know or have never had anyone tell them the pro's and cons.
Good luck on your future purchase!