OK, you are looking at a 98.5 or newer to get teh quad cab in a 2500 with the cummins. This lets you in to the ISB series, should be 235 hp. If you don't mind the noise, you cannot beat the all around power. Lots of low end, real world pulling power, and the best part is, not a v-8.
In 98-99 the tranny option was a 5-speed, 6 speeds started to appear around late 2000 if I recall correctly. Fuel mileage is hit and miss, some, like my 01 are great, some suck monkey nuts. I run between 23 - 26 mpg, friend of mine with a 98.5 gets 12 - 14 doing the same kind of stuff. Both trucks are 2500/ISB/5-speed/4x4/ 285/75/16 tires.
And, as a useless side note, if you buy a 3/4 ton or heavier truck for fuel mileage, you need help.
Back to the truck. The front ends are lame. I drive my truck, work it hard every day, and I will tell you, they need the upgraded ball joints, and you can get a Luke's link, or other options to repair the track bar in the front. If you truly set your mind on a truck like this, check out
http://www.solidsteel.ca/. These guys make steering braces and updated track bar kits.
Other than that, lift pumps are ad on these trucks, but cummins has introduced an updated pump, that flows better and lasts longer than the original. Get a fuel pressure gauge for the lift pump, and if anyting goes wonky change it. The VP44 injector pump will not survive without the lift pump functioning properly. Last friday, I performed VP44 transplant surgery for the 17th time, on a truck where the lift pump had gotten weak, and it ate up the injector pump. Pricey fix.
They are noisier in the cab than the other brands of trucks out there, but that is a small price to pay for the pulling power. It will haul an 18 foot boat like its not even there. In fact, the boat may as well be a tea towel flapping in the wind back there.
As far as around town, I have found that the dodge 4x4 has a way tighter turning radius than the ford or gm products, making my life a whole bunch easier when i am hauling the bobcat or excavator around and need to turn around. even with the quad cab long box, and a trailer that measures 21' from hitch to tail, I can turn it completely around in the width (shoulder to shoulder ) of a residential street.
Hopefully, although way too long, this clears things up a bit. Good luck in your search.