Matt-- I sent you an E-Mail, explaining your available options using the stock OEM 18x7 rim. Basically; keep the 285-series width, and increase the aspect ratio to either 65-series (LT285/65R18, 32.5" O.D./60 lbs) or 75-series (LT285/75R18, 35" O.D./66 lbs). Just be careful of "unsprung weight" in extremely heavy LT-series tires.
Lightweight "P-Series/P-Metric" tires are a much wiser option for the small sporty VX like the Pro-Comp A/T in P285/60R18, 31.3" O.D./43 lbs) or the awesome General Grabber AT2 in P275/65R18, 32.1" O.D./44 lbs). Riff Raff