I have an enclosed trailer with my tool box, air compressor, and some other things. The truck is 2wd but has 2" spring spacers on the front and 31" tires with brand new rancho shocks.
My question is, do I need to install a block or another leaf spring in order to not bottom out the truck? Any info is greatly appreciated!!! This is my first ranger

 

I would look at the drivers door sticker, find the AXLE code, then look here:
Ford 7.5 & 8.8 Inch Axle Tag & Door Codes

You want a 3.73 or 4.10 axle for towing, especially with 31" tires
3.55 and lower are for MPG at highway speeds, which was common on 2WD 4cylinder vehicles, point of 4 cyl engine is better MPG.
This would be bad for towing.

Larger tires and axle ratios, assuming stock 2WD Ranger came with 14" wheels so 26" tire diameter:
3.73 axle with 31" tires turns into a 3.13 axle
3.55 axle with 31" tires turns into a 2.98 axle

So not sure the weight on the back end would be a problem, usually tongue weight is under 200lbs