After you add the fuel stop, presumably around or before the warning triangle, go into the fuel stop and enter the number of gallons in the Fuel Added box. The warning triangle will reappear at the next logical place. Trip Wizard will not read the GPS. If you have a Rand McNally, there is a reasonable way to export the Trip to be read by the Rand. If it's Garmin, you have to use Basecamp, and much more complicated. The RVLife App would be a nice addition.
2015 Tiffin Phaeton 42LH - All Electric w/tag & RettroBands
2016 Jeep Wrangler Unlimited Sport w/mods