My G670's have been fine too - replaced the fronts last year and the rears are due now at 7 years and 58k miles.
The G149 is designated a "Regional Service" truck tire by GY bit they also say it is "suitable for Class A motorhome". The design is a simple, straight deep rib, excellent for channeling water out from under the tire. I would have no qualms at all about using that tire.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL