I just bought my 2006 1500 SLT Quad Cab Short Bed 5.7L Hemi about 2 months ago with 176k miles on it and it runs like it's brand new. These trucks last a long time if they are taken care of properly.
Ask if the water pump has been done (should be done on hemis at 100k I've been told).
Ask if the plugs have been done recently. Also, check the valve cover gaskets and the rear pinion seal.
Other then that, just check for normal issues. If anything electrical doesn't work, it could be a bigger issue. If their is any clunking or clicking in the drivetrain, beware.
Also, make sure you start the truck ice cold, once it's sat for 5 or 6 hours turned off. Listen for any ticks, taps or knocks within the first 30 seconds of startup. Make sure there is no lifter tap or rod knock.
Also, check for any smoke (white, black or blue) coming from the exhaust