My main thought process when four wheeling is:
"as slow as possible but as fast as necessary"
Meaning that you go slow to maximize your control of where the truck is going and minimize damage both to your truck and to the terrain you are traveling on. But, sometimes momentum can be your friend and you have to give it some skinny pedal!
The one BEST four wheeling mod I have made to my truck is ROCKSLIDERS!!! Without them, my rocker panels would be beat so bad, I am not 100% sure that I would be able to open my doors, LOL! I have a crew cab shortbed 2500HD Power Wagon with Carli 3" lift and 37s. I go on tight Jeep trails with it, LOL!
Your truck's wheelbase is the best possible when it comes to wheeling a full size pickup!!! The generally accepted ideal wheelbase for a wheeling rig of any sort is roundabouts 102" so, you are not that much over it! (WAY better than my truck's 149.5" wheelbase! Longer than the overall length of an entire Jeep Wrangler YJ or TJ!!!)
One thing to be wary of is side hills- the forward biased weight distribution of an empty pickup will cause the light rearend to tend to slide down loose surfaces, especially on muddy trails!!! (this weekend I went wheeling and had to have the rearend of my truck winched sideways 3 times to keep my bedsides off trees! I am actually considering a rear mounted winch specifically due to this tendency!)
If you don't feel comfortable tackling an obstacle, don't be afraid to ask for help (in the form of a spotter) or to take a bypass route (if one is available), remember the old phrase- discretion is the better part of valor!
Memorize the terrain- with the big hoods that Dodge graced our trucks with, forward visibility is somewhat less than ideal so, always look well ahead and try to memorize the terrain that you are coming up to! My visibility of trail obstacles is such that I have 20 feet worth of trail in front of me I can't see so, I have to memorize 20 feet at a time in tough sections.
Picking your lines- (within reason) always keep your tires on the high points of the terrain. Doing so will keep you from dragging your rear differential, your rear shock mounts, your front lower control arms, and frame cross members, etc. Pick a line through the terrain that puts your tires on the high points but does not put you into a tippy situation.
Air down- if you have access to a way of airing back up, drop the air pressure in your tires some. This will help them to be able to conform to the terrain better, helping to give you more traction, and minimize damage to your tire and to the terrain you're wheeling on! I wouldn't go crazy low since you want to maintain some pressure since ground clearance is really going to be at a premium! (I drop to around 12psi BUT, I have 37s. If I were you, I'd likely drop to 20psi at the lowest, hopefully somebody that wheels a rig similar to yours will chime in as to what pressure they run) If you have no way of airing back up, then don't air down as your tires will not be safe for road travel at the lower pressures.
Do NOT wheel alone!!!!
Have fun!!! You are going to be amazed at what you and your truck can do!!!!