My first diesel is the truck I currently own and I love it. I don't know how much improvement the newer trucks offer, but I can tell you what to expect from 10-15 year old truck. My truck was meticulously maintained by the previous owner and he still offers to buy it back from me when I see him. He sold my truck to get into a 3500 DRW 2005. Anyway, I bought my 97 with 155,000 on the clock and I have 211,000 now, so thats 55,000 in 3+years.
In that time I have done tires, shocks, fuel solenoid, starter, alternator, batteries, belt, tensioner, front hubs, rotors, pads, calipers, new hard lines, rear driveshaft (u-joints, pinion yoke, seal) all of which falls under routine mainentance for a 10-15 year old truck with 215,000 miles. I added gauges, BHAF, #11 plate, AFC spring kit, brake controller.
Next up I have to do front inner axles seals and will probably do the ball joints, front u-joints while I have it all apart, might even do the steering coversion (Y to T) and a new track bar... ... My truck could use new paint on the hood and the roof (the whole truck should be re-shot, truthfully). I'd like to upgrade the headlights, do an 3-piece exhaust manifold, add a pac brake, and know that there is a clutch job lurking somewhere in my future (still on the original clutch).
I'd imagine that most trucks of this vintage could be in a similar place. And this is not from abuse or neglect, just the maintenance needed to have confidence in the vehicle to go anywhere without concern.
The back seat would be marginal for 1 kid and probably not doable for two kids, especially without the 3rd door (pre 98). Finding a 98 12v is next to impossible, so don't hold your breathe on that one. I love my truck and I wouldn't trade the simplicity of it for the newer truck, but you have to know what you are getting into. I feel like I am slowly restoring the truck and I am OK with that, but it might not be for everyone.
Good Luck
Chris