Alternators are not as efficient at lower engine speeds. Having two allows you two recover power faster when running high-amp draw accessories like a plow, spreaders, winches, compressors, etc., basically things that are used at low engine speeds or even at idle. Since it is highly unlikely you are charging your RV batteries with your truck, having two alternators has no advantage for you.
2012 CCLB 3500HD Z71 Appearance Package Dmax/Alli
275/70-18 Cooper ST Maxx - Air Lift Bags - Viair Onboard Air - B&W Turnover Ball
Wishing it sounded like my old LB7 with Banks exhaust. . . . . . .
MY FUELLY PAGE LINK
1984 C20 6.2 J Code TH400