Well, you're in luck.
I currently have a 2007, Quad cab, 4x4, 5.7L Hemi (345hp/375tq), 5 speed auto, with 3.55s. It pulls my 17' hybrid much better than the 2006 Chevy, extended cab, 4x4, 5.3L (295hp/335tq), 4 speed auto with 3.73s it replaced. The 5.3L just seemed down on power compared to the Hemi; much more than the specs would lead you to believe, even when going from 3.73s (Chevy) to 3.55s (Dodge). The 3.55s are the ones to get for light towing IMO. The Chevy in 3rd was at about 2800 RPM @ 60mph, the Dodge is about 2400 RPM at 60 mph in 4th(?). Neither truck will use their top gear when towing. The RV is a light weight, but it is a 2010, and therefore is a full 8 feet wide.
I use the Torque App to keep an eye on engine and transmission temperatures while towing and, as you can imagine, neither truck had any issues there. The 5 speed transmission is the biggest improvement. With GMs 4 speed 4L60E, it had 2 ratios to use. Direct (3rd) and 2nd. With the 545RFE, it uses 2nd, 3rd and 4th depending on the terrain and wind. The Dodge also has a bigger fuel tank.
Both get about 10 mpg pulling the RV in the pictures.
I also towed this RV for a few trips with a 2006 Pontiac Torrent. It did ok on flat terrain with no wind, but was all over with side winds and really worked hard on grades. I only used it for short local trips on the prairies, but there are a few valleys here, and it got up to 3/4 on the engine temp climbing them even though they were short climbs. Definitely tail wagging the dog some there. I knew it was only temporary so I didn't invest in a WD hitch though I should have.