There are some very good,detailed dimensions on line.
Just do a search for "ram truck dimensions" for the model (s) you would like to compare.
Also on youtube, people have posted videos of taking measurements.
This is probably much more useful than I could provide.
The Ram 1500 Quad Cab, Standard Bed (5th Gen, DT) is a versatile full-size pickup truck designed for work and everyday practicality. Its rugged, sculpted exterior features a bold front grille and aerodynamic lines that blend strength with efficiency. The Ram 1500 (Quad Cab, Standard Bed) has a...
www.dimensions.com
Some of the 2500 / 3500 models with a short bed come with the ram box feature, which in general is really nice, but might not be what you need.
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Before you just "assume" that a 2500 will be the right choice vs 3500 SRW with air leveling, consider to run the match a bit tighter against the actual axle ratings and capacity, which will vary quite a bit, especially if you get a cummins version vs hemi version.
This is not a perfect way to do the math, but it is not so far off.
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For the items and people inside of the cab, I assume 200 lbs per person, and 50 lbs of stuff in there with them.
The driver is already counted in the factory rating, so I use 750 lbs for 3 people and stuff, apply 50% of that to the front axle, 50% to the rear axle.
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Everything in the bed I assume as going to be carried by the rear axle, so in your case ~ 1 000 lbs in the bed - so on the rear axle.
50% of the weight in the cab goes to the rear axle, so ~ 400 lbs
Trailer tongue weight goes to the rear axle, so almost another 1 000 lbs
So your rear axle will be carrying ~ 2500 lbs , so it needs at least this much rear axle available capacity to do what you believe you need today.
This is not exact, but a decent first order estimate.
I would definitely get the air leveling feature with that much routinely being done.
