We had a 1993 Chevy 2500 ext cab 4X4 LB with a 5.7 auto purchased new. We hauled a Lance Squire 4000 (9-1/2') with a dry base wt before options of 2353 lbs and when loaded with the options was 2784 lbs dry on the shipping tag. Add your water/gear/food/my 2' X 8' steel rear porch with our Honda EU2000 generator on it and the 22 X 30 X 14 storage box filled with a hookup needs 2 extra 30 amp powercords, leveling 2 X 10s, 12 ton hydraulic jack, etc. Yup, way over 3000 lbs. I still have the Lance brochure as I keep them for every RV and vehicle we purchase. They come in handy!
Truck hauled that Lance setup to Alaska and back from Michigan twice and to every state of the lower 48. Much of Canada also. Sold the truck to a farmer friend about 50 miles north of here in 2004 and he's still using it to haul loads and has over 300,000 on it now and still has the same engine, tranny, and airbags. We own the land next to his farm and see him and the truck a lot. We drove the truck over 100,000 miles with the Lance on. Never had one problem with the truck or it's handling. Yes, I did do some upgrades to the truck before loading the Lance. 265/75/16 "E" Michelin tires when the OEM 245's wore out at a little over 30,000 miles. Added Air-Lift Systems 5,000 lb airbags and very heavy shocks (Ranchos). Inflated the bags to 40-45 lbs.
The OEM tires are usually the lowest limiting weight capacity.
Assuming your frame etc is in good condition, you should not have a problem hauling the 850 Lance on your truck but I would suggest the larger tires 3415 lbs vs 3042 lbs each (373 lbs each tire), good airbags, and very heavy duty shocks. Tried Timbrens (rubber type overlaods) and found the airbags head and shoulders better as they are infinitely adjustable to loads and road conditions.
A superb CC LB 4X4, GM HD Diesel, airbags, Rancho's, lots more
Lance Legend TC 11' 4", loaded including 3400 PP generator and my deluxe 2' X 7' rear porch
29 ft Carriage Carri-lite 5'er - a specially built gem
A like new '07 Sunline Solaris 26' TT