go up to 84 to 87 and avoid the GW altogether. I crossed the GW a long, long time ago pulling a popup. Swore I would never do it again.
Also, for references, pick up a copy of the Motor Carriers Road Atlas from any truck stop. There is a section that lists all the low clearances for each state and references the map location of that low clearance. I use it exclusively when planning a trip.
John, Joyce & Libby the Yellow Lab. - Fulltime since `08
2005 Kountry Star FW-35LKSA by Newmar
2012 Ford F-450 Lariat