I agree that talking to
@crikeymike or David Otero about a Dobinson setup is a good place to start. After discussing your budget, intended use, and weight of your truck, they can suggest an appropriate setup. Dobinson has a wide variety of setups, are cost effective, and perform well. It’s worthwhile to invest in quality shocks if you can afford them, like Dobinson MRR’s.
Icon springs are meant for light to medium weight rigs. Since you’re adding significant weight, Icon will likely sag too much.
For overlanding, as opposed to rock crawling, 35’s would keep your lift height and center of gravity lower. With a rooftop tent, lower CG will be important to keep the dirty side down. 37’s require more lift, more modification, and considerably more money to get it done right. A 2” lift will fit 35’s, require less castor correction, avoid driveline vibration issues, less bump stop extension, and maintain balanced suspension flex.
With 35’s, you can return to stock gearing, cheaper than re-gearing the differentials, with a set of transfer case high range 10% under-drive gears, which will give you about a 4.56 ratio. 4.11 is stock. While in the t-case, most people install a set of low range 25% gear reduction for more control offroad.
A set of rock sliders and belly protection are important on the rocky Colorado trails. I’d start there before adding the lift.