Hello! Got a quick question...

I've got close to a thousand miles towing my travel trailer now, and aside from a radiator hose letting lose on me when I first got it because my fan clutch was bad, my truck doesn't seem to mind the pull. There is a grueling 10 mile stretch of 6% grade though where I'm pretty much pulling in 2nd gear full throttle, holding it right around 4,000 RPM the whole time. Is it worth it getting an EGT gauge? Is it even an issue on NA gas engines?

 

I think you are referring to a non-turbo gas engine, if so, EGT is not a performance measurement. Engine temp is primary gauge for monitoring engine health, at least for a stock setup.
I recommend: install an OBD sensor that monitors transmission temp. There are some inexpensive sensors that send data to your phone. Get an aluminum aftermarket differential cover. This will allow greater fluid capacity and aluminum will keep the fluid cooler. You can also get a differential temp monitor if you want to be extra.
What rear end do you have? Do you ever get peeling paint on your diff cover? What gear oil are you running? How close are you to your max towing capacity? Sorry for the questions, more info will help us understand your situation better.

 

Gotta be careful with rear diff covers. Gale Banks has a series on youtube on them. The 'high capacity' covers can actually be worse for your rear diff, than the stock cover.

 

The front and rear diffs were actually just overhauled at 184,000 miles (195,000 miles on the clock now)

4.56 front and rear, Motive C8-456 front, Detroit True Trac 913A368 with Revolution Gears rear, full Timken bearings front and rear, and Shaeffer's oil

4/1 HD leafs, 10ply E Falken tires, and stock diff cover (I've seen the Banks video), Rancho RS9000XL front and rear

Running a severe duty fan clutch and a 180 thermostat, it never ever crosses over mid point on the temperature gauge even fully loaded pulling the grade. K&N Gold HP2004 oil filter and valvoline full synthetic every 5,000

That's pretty much it, lol