2014 ram 1500 3.6l towing a 2013 trailmaster 24 rblg

I tried to look up your TT but could not find info. What is the weight and width?

I have been towing a 16' TT (7' wide) about 2700 lb with a Highlander V6. This engine is very similar in output to the 3.6L especially at 3000 rpm and above (my 3.5 isn't as torquey at 2000 rpm as the Pentastar, though). Although it has done the job, I would not want to tow more trailer than this. And I am pretty tired of 40 mph @4000 rpm up the long grades in the Rockies (but everyplace else it does well enough @ 60 mph... 65 is kind of pushing it though). So I'm actually looking at the 5.7 hemi right now.

One factor for me is the heavier transmission that comes with the 5.7 (or the diesel, for that matter). "Flooring it" to go faster up those grades has not been an option for me, because my tranny was getting too hot. I suspect the situation would be the same with the Pentastar.

If an improvement in mileage would be the motivation, how many miles would you have to drive to break even after the additional cost and depreciation? Those specs seem pretty close.

I think it will do fine. The smaller, more efficient engines are power houses these days and they don't have to spin as much to do it as they once did.
Compare the output of that eng. to both small and big block V8's of years past (80's~90's) and you'll see it's very competitive.

Will it do it yes. BUT it will do it higher rpm. Just from looking at a horsepower graph it seems it will need about 3500 rpm just to go interstate speed on flat ground. Mild rolling hills it will run 4500 rpm. For a more substantial grade you will be about 6000 rpm and still possibly slowed down. So on a 5% grade it will need about 6000 rpm and a 5% grade can often be 5 or more miles long. It shouldn't really hurt the truck but can your nerves handle it.

How often do you tow? If it is only a handful of times per year I would say go for it. If it is more, I would consider all my options.

Will they let you do a test drive where you can hook up your trailer and see how it does?

Do you plan on hauling that ATV in the bed of the new truck too? I think you're into 3/4 ton or HD payload F-150 range for that.

The 2014 GM 5.3L IMHO offers a far better balance of real world fuel economy and towing performance. I really like Ram's 8-spd trans, but the V6 will need every bit of that 6000rpm for towing a high walled RV.

If you don't mind rev'ing the motor to 4-5k with your foot near or on the floor when max power is needed, you'll be fine. Such motors are designed for this, so there is little worry, other than what you let get into your head.

The 8-speed transmission has enough low ratios to make the high-rpm torque usable, and offers ample multiplication. For towing in the hills, 305>295 so it could actually pull better as long as the RPMs are kept up.

8 speed sounds like marketing for a daily-driver type transmission. The six speed on my 2013 dodge never goes past 4th gear while I'm towing my little 20 footer with the 5.7 hemi... unless it's on a downhill grade :)