Depending on the model year, there'll be something covering the center of the steering wheel... could be a round horn switch, could be a larger plastic covering which also functions as a horn switch... it varies quite a bit, as the T600 was in production from 1986 through 2007. Once you've got that removed, you remove the steering wheel nut. Don't remember what size socket you need off the top of my head.
From there, you take a steering wheel puller, run bolts through the small holes of the steering wheel and the puller (3/8" standard thread, IIRC), run the big bolt through the center of the puller and make sure it's lined up with the steering column, turn it clockwise, and it'll pull the steering wheel off.
If you don't have a puller, a deadblow hammer can often get the steering wheel off... don't buy the Snap-On one, though - not worth it - get the $11 one from Harbor Freight. Once that nut is removed, give some good strikes in an upwards motion to the bottom of the steering wheel.
You open up the steering column and find it in there...
A Kenworth T600 can be purchased from a truck dealership and from Truck Paper, Truck Trader, Ranges Trucks and Accessories, Truck Sales, Ebay and Commercial Trucks.
It's 3 lbs, 12 ounces for the T660, and that's what it should be for the T600, as well.
right hand side of driver door
Peterbilt never made the T600. The T600 was built by Kenworth, and it ended production in 2007, at which point it was replaced in production by the T660.
It'll be in the vicinity of 11 gallons.
Between 16,000 and 18,000, depending on options. For example, the engine displacement will affect weight. If you get, say, a C12 or C13 Cat engine, it'll be lighter than the C15 or Cummins ISX. The transmission.. an 18 speed will have more weight, etc.
The tallest point can be up to 13'6... typically, they'll be between 13'1 and 13'4 with a stand up sleeper.
Call a Kenworth dealership, give them the last six of the VIN. They should be able to tell you what it was keyed for from the factory - if it was re-keyed at any point, they won't know.
There are many types of semi trucks available for purchase from Kenworth Trucks. A few of these semi trucks are T880, T680, T600, T700, W800 and also a W900. Kenworth dealers will also sell used trucks from other manufacturers which were traded in. Aside from selling Class 5 - 8 Kenworth trucks, some Kenworth dealerships are also dealers of Hino trucks.
Depends on model year. Keep in mind the T800 and T600 went into production the same year - 1986. Earlier models will have a switch in the floor, to the left of the clutch pedal and closer to the driver's seat. More recent models will have it in the steering column.
Call Kenworth with the last six of the VIN... that's the only way to know for sure. Not every single vehicle of that make and model will have the same requirements, nor will they even within the model year.