Nothing smaller than a 25', the smallest of the large trailers meaning it has large storage tanks, large running gear, and a queen or twin bed option while still providing a nice sized living room.
So that's why we have the 25 and are in it 6-7 months a year, an excellent all-around Airstream easily towable with a 1/2 ton truck or large SUV.
We tow with a Ram 1500
Hemi 120" wheelbase making for a very maneuverable combination, using a ProPride (Hensley style) hitch for absolute stability in any traffic or weather. We have the full awning package for sun protection, MaxAir vent covers for ventilation in all weather, propane and electric conv/microwave oven, queen bed because that's how we like it, 16" Michelin LT tire conversion for reliability, and converted the original dinette to the recliner configuration of the 30' models for comfort in extended use.
We had grandchildren visit with the other interior setup and it was fine. We will "make do" when they visit with this one.
Some prefer the biggest trailer/truck combo they can get, some somewhere in between, and it works well for all of us. We like this package very much for long distance travel, terrific maneuverability with and without the trailer hooked up, and comfort when we settle in.