To original poster...
Last summer I traveled through the BC mountains in my 07 Dodge Ram 2500 w/ 5.7 Hemi, pulling my 7500lb (dry, probably 8500lb loaded) 5'ver. Did OK but the hills were a real strain. Long climbs in the mountains slowed us right down while the engine screamed.
That convinced me to go diesel. Sold the 07, picked up an 04 Dodge Ram 3500 SRW with a Cummins 5.9. Pulling the same 5'ver for my vacation this year was a whole different ball game... I wasn't going through the mountains mind you, but any hills we climbed (and there were some good ones) the truck didn't even notice them.
So, said all that to say that the 5.7 gaser will be fine on relatively flat ground but will struggle on the big hills. Safety shouldn't be an issue but performance will.
Good luck with you decision.
