Re: Serious Advice Needed!
The F-450 is more of a status symbol and is overrated. Unless you plan to tow 20K with it on a regular basis, the harsh ride will hurt your body after a while and you'll want to sell it.
If your 250 is serving you well with no issues, I'd keep it. Run synthetic oil where possible (rear gear oil, engine etc) as it will prolong component life. I'd keep the 7.3 diesel as well. If it's not the best diesel that Ford has got from International, it's in the top two. It has the least amount of problems than the 6.0L and the newer 6.4L twin turbo. The 6.4L eats more fuel even though it's a smaller size. This is due in part to the twin turbo design, as one of the two turbo's are always giving boost, which eats more fuel. A magazine recently tested a Harley Davidson 250 with the 6.4 and they achieved 15mpg highway and only 11 around town. For a diesel, it could be MUCH better.
If the rear of your truck seems to sag from age of the springs, etc, then you can get air bags for a smoother ride and assist the springs to keep the truck level, or install helper springs over the OE springs.
If you're hard up with getting a new truck I'd go for a SRW F350. If you don't need the 4x4 system, skip it, as it'll be a maintenance hog in the future. If you want used and don't tow the trailer often, get the V10 engine. It has nearly the same torque as your 7.3L, eats a bit more fuel but costs significantly less to own and operate than a diesel.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!