Originally Posted by AlfaGold
Alfa Leisure, of Ontario, California, manufactured the Gold series of fifth wheels between 1975 and 2008. The last Gold series produced by Alfa included four models: the Gold 3RL 319, the Gold, 35RL 324, the Gold 35RLIK 323 and the GOLD 35RL 321.
None of the Gold models listed above have GVWR more than 15,000 pounds, so yours must be an older, heavier model.
GCWR = gross combined weight rating, or the combined weight of wet and loaded tow vehicle and trailer.
To tow a 16k fifth wheel, you need a dually with a diesel engine and a GCWR of 26,000 pounds. You're apparently looking for an older dually. The 2008-up Ford F-450 factory pickup would be ideal for that trailer, but that will cost you over $30k. The only F-450s available before 2008 were chassis cab trucks with an aftermarket bed/tow body. The factory pickups came only as CrewCab diesel 4x4s, so not much choice for a less expensive F-450 factory pickup. However, before 2008, lots of F-450 and F-550 chassis cabs had an aftermarket dually pickup bed installed, so they looked just like a dually pickup except for the 19.5" tires. And some of those were SuperCabs and regular cabs and some were 4x2.
Before 2005 model year, Ford F-350 "one ton dually" diesels had a GCWR of only 20,000 pounds - not enough for your 16k 5er. The F-450 chassis cabs had a GCWR of 26,000 pounds. It's easy to load up an F-450 chassis cab with bed/tow body and family and tools and jacks and "stuff" to weigh over 9,000 pounds, so with a 16k trailer that's 25,000+ pounds GCW. So you need an F-450 or F-550. (Or a Dodge or GM 4500 or 5500 with at least 26k GCWR).
The '99 thru early '03 F-450 diesels had a 7.3L engine that is in high demand. It's an excellent engine. The rear axle in the 7.3L F-450/550s was a huge heavy sucker with a 4.88 ratio. Later, some F-450s were made with 4.30 ratio, but the GCWR fell 24,000 - not enough for your requirements. You need the full 26,000 to meet your goal of having enough power to pull that 16k trailer over the hills and passes at highway speeds without bogging down.
Later than 2003.25 Ford diesels had a 6.0L engine with a reputation of being trouble-prone, so they are in a lot less demand and therefore might cost you less up front. I would keep looking until you find a '99-'03 7.3L.
So the short answer to your question is to look for a '99-'03 F-450 or F-550 with 7.3L diesel engine and 4.88 axle ratio that has a tow body, or maybe a flat bed with a 5er hitch. Or some other body you would be willing to discard and replace with a tow body or flat bed. (Lots of dump trucks are available, some with very low miles, but most are gassers with less than 26,000 GCWR.)
Because of the short legs of the 4.88 ratio, you'll love the towing capability of that F-450 or F-550 when dragging your 16k 5er. But it's not a particularly good commuter car for driving unloaded.
Here's a link to the only F-450 7.3L I see on ebay right now:
Ford : F-450 F-450 Cab & Chassis in Ford | eBay Motors
That one sounds fishy - 211k miles in 2005 but only 218,500 now? Was it stored in a barn for the last 8 years?
But thousands were built with tow bodies specifically for towing heavy RV, horse, and race trailers. So keep looking, and you'll find some with SuperCab or CrewCab, and a trim level you're willing to pay for (XL work truck, XLT boss's truck, or Lariat fancy leather trim with trip computer).
Note: The cab and interior of the F-450 and F-550 chassis cab trucks were identical to the F-250 pickups with the same trim level. Not true of the GM and Dodge 4500s. The big difference in the F-450 and F-550 is the rear axle - Dana 80 vs. Dana S135. Either one with 4.88 ratio would have no problem towing your 16k trailer over Wolf Creek Pass or Vail pass.