If you're going 300+ miles regularly plan on getting a bigger truck too.
Not saying a bigger truck is a bad idea, but it's more about tow rating and what you are using it for.
My 2011 VW Touareg has a better ride, is more responsive, has better gas mileage and a higher tow rating than my 2004 Suburban did.
2017 VW Touareg stats: Towing capacity: 7,716 lbs - MPG: 17 city / 23 highway - Dimensions: 189″ L x 76″ W x 68″ H - Horsepower: 280 hp
The 2011 has made three fully loaded trips from Michigan to Alabama when we moved, pulling an enclosed trailer. Empty up to MI but fully loaded heading to AL.
For example...
SUV loaded, check
Trailer side door, check
Trailer rear, check
No problem pulling at highway speeds.
Also a round trip from Alabama to Michigan and back with the P5 in the enclosed trailer to hunt my farm one last time before we sold it.