Few notes now that others experienced with what or near what you have have now commented.
First, everyone seems to be saying that you should try it out before you spend the money. It's probably not necessary.
Also, a lift on one of those trucks is probably going to be more for looks than anything else. I believe the only people who make a functional suspension system for those leaf sprung trucks is Thuren Fab. Otherwise all you're gaining are approach and departure angles. You will probably need a leveling kit for the 35s to fit properly in the front. But you may be happy with how your truck sits without going any higher.
Here's a pic of my f250 7.3 with 35" bfg tires. Like I said, I don't think it was lifted. Only leveled. As you see, it wasn't a small truck. Your tires are going to give you quite a bit of height.
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The last thing I wanted to touch on is that I believe the mounting for a Four Wheel camper is actually to the bed from the factory. Like the put eyelets or brackets in your bed and that's how it's done. I don't think they do it another way for their brand. They may if requested though.