My Ranger is rated at 5560lbs, way above the 3700lbs you quote. honestly, anything above 2000lbs needs trailer brakes with my ranger with the larger breaks and such. With a 91 2.3 I wouldn't throw any more than 1500lbs behind it. Just because your truck can move the load doesn't mean your truck is capable of safely towing it.
Nothing bothers me more than seeing a small truck struggling to keep up with traffic towing too much weight with too little suspension/frame/brakes.
Nothing bothers me more than seeing somebody zooming in and out of traffic, flying by, carrying a huge trailer and thinks he's safe because he has a big truck.
They're called speed
limits. Only highways have speed minimums, 45 to the last of my knowledge. Nothing wrong with driving slow and careful with a larger load. I don't care where you're driving from/to, it's not worth risking lives over. I'll just drive a little slower and leave my room like you're supposed to.
Ranger's all run predominantly the same frames, brakes, and wheel bases. 4 banger Rangers will stop and handle the same load as a 5.0 v8 swapped truck. It just will annoy impatient people getting moving, but I guess that goes along with your user name.
2,000lbs is nothing, I've had 1,200 just in the bed. Below, a 4 banger, stock. Kept up with traffic just fine, even on the highway 55mph, no reason to go any faster, just poke along behind a semi or in the right most lane. That J-10 went across the state, had the front clip on then, rangers bed loaded flat and more parts in the j-10's bed and cab.
Safety is not a specific weight, you can crash with no load at all. It's all in the adjustment of the nut behind the wheel.