Thanks for the information. We can only respond with the information provided, in a thread. Going back and looking at your profile, or previous threads is something few do, and in your case, none provided.
Kudos to your RV Dealership, for stressing the importance of the Truck hauling this beast of a Truck Camper. (Oh, yeah, I own one too!! & Love it.) Why would the Lance Dealer be doing this? Easy, the Lance 1191, like many TCs, is a lot more weight than what they are posted as. I would encourage you to;
1. Weigh Your F250 before loading your new Lance 1191. Put fuel in the tanks and stop at a Cat Scale, or something.
2. Weigh Your F250 after loading the Lance 1191, after you have a full load of Potable Water and Propane. Be ready for a surprise.
3. Compare the difference with the original weight of your F250 and now with the loaded Lance 1191, with your Ford Door Pillar Tag, for weight and axle weights. Then add 1000 lbs (this figure has been derived by others, on this forum for the SWAG wt) for all the clothes, food, junk, jacks, levelling blocks and cooking stuff one would normally load. Be prepared for an even bigger revelation.
This situation comes up, here in the Truck Camper Forum, often. Too much camper for the truck and then the person spends more money on the truck to make it work, than the few hundred dollars difference between the cost of a F250 and F350. One poster, on this forum, began the same discussion and information here went back to his Ford dealer and swapped out to a larger Super Duty. He said later he was glad he did.
I don't wish to start one of the frequent debates, either, on whether SRW or DRW would be the better Truck, as you already have made that choice. The next two things to consider, the difference in the Brakes between the F250 and F350. I am not that familiar with the newer trucks, but when I had my three F350s, the deciding factor then, was the larger brakes. The second is tires and wheels. Many doing what you are doing, immediately change to a more capable wheel and tire combinations. Many threads here on that discussion. Many opt for the 19.5s, by the way come standard on the larger Ford Super Duties.
The next item, re-certifying your suspension and Fed Door tags. Not Possible. No matter what anyone will tell you. Maybe your Ford Dealer is telling you to do this to increase the safety factor and margin. Kudos for them. But no, they can't change your certifications. Some have tried and have done extensive research. Check with another person here; btggraphix, as he had a recent thread on this.
Warranty, yes, the dealership you are dealing with will probably work with you, in getting things capable. But here is the rub. If you travel away from this Dealership, like out on the road, and need service at another Ford Dealership, they won't give you the same perspective (garnered from 18 years of vintage racing around the country with F350s pulling heavy race trailers) if you have some warranty issues with your drive train. Also, the type of wear that occurs by over-stressing your suspension will begin occurring far down the road, 45-60k miles. In the area of transmission, differentials, spindle bearingss and steering components.
The great thing is, your situation is very well documented in many threads pertaining to doing just what you and your DH are attempting. You came to the right place for information and help. But you will hear things you might not want to hear, from some of these people trying to help, (like I am doing now) then maybe this forum is not for you. But at least you will get great information from a whole bunch of people, like the moderator, Steve29 and many others.
I love my Lance Camper 1191 and spend a lot more time in it than many. Love my Ford Super Duty and came here to get an education 2004 to 2008, before loading the Lance. You will probably enjoy the change and freedom you will have, in switching to a Truck Camper, over your previous Camper choices.
Hopefully you will report back what those weights turn out to be and the type of modifications you did and your impression of them.
b