Questions about Diesel Maintenance

My next truck (4x4, CC) has to have a minimum 3000 lbs. of payload. That leaves me with either a 1 ton diesel (3500-4000 lbs.) or a 3/4 - 1 ton gasser (3200-4000 lbs.).

I've run my gasser vs. diesel numbers as far as purchase price, MPG (towing & empty) and resale.

I'm familiar with what's needed to maintain a gasser; however, never owned a diesel. Here's what I know, don't know, about diesel maintenance:

1. Oil costs are approx. double vs. a gasser due to twice the oil capacity.
2. Oil filter. I assume these cost a bit more than a gas oil filter?
3. Fuel Filters. Assuming DIY replacement, what can I expect to pay for filters? How often?
4. DEF. 2-4 cents of DEF used per a gallon of diesel??
5. Valves. Under normal operating conditions is adjustment ever necessary? If necessary, cost?
6. Injectors. Under normal operating conditions is maintenance/replacement necessary? If necessary, cost?

Other diesel specific maintenance items I may have overlooked?

Thanks!