without knowing how your Ram was equipped, it's not easy to recommend something.
i tow my 23SS, which weighs about the same as the 21SS, with a 5.3 v-8/ 3.73 rear ended Avalanche and i live in Calif.
so i have to pull over the Sierras, Cascades and Siskiyous and i have no problems.
if you don't have a Hemi in your Ram, then you might need something bigger. if it does have a Hemi, can't see why you'd need anything bigger, unless you do plan to upgrade to a bigger trailer in the future.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC