I daily drive my 3500 (single cab, long bed, single rear wheel, 4x4) at home in the sticks. I also have to use it for business, in the Bay Area and Los Angeles. Parking is more of a pain than for small cars, but it's really not any worse than my F150 with a 6 1/2' bed was.
Fold your mirrors when needed, and I always try to back in. The camera is awesome.
As far as mileage, I was shocked when the computer showed me 18.5 commuting between San Jose and Palo Alto for a week of rush hour traffic. It's not stop & go, but is mostly slow rolling along (20-40 mph) and the Cummins idles at 10-15, so I'm really not using much throttle in bad traffic. I try and avoid massive speed changes, and just go with the flow. That said, I'm not afraid to nail the throttle to get into a spot I like.