Hi Mike, well firstly the Nuvi 310 made by Garmin has been very useful for post Chase preparation by direct input lat/long will show you the lay of the land where GFS sugests best potential is.If for instance GFS plots for area X where thunderstorms might evidently bullseye I can instantly see if its going for orographic trigger/convergence on a range.
The Data base of knowledge for Fuel,lodgings,landmarks,lookouts,Food,shopping centres,entertainment(maybe this should include routing to biggest storm
)Transit,Hospitals,ATM's is quite extensive.
Chasing outside the regular area or simply taking a scenic route certainly helps find your way when signposting is poor.Determining a road to take prior to arriving at the turn and knowing its general direction out chasing is a huge benefit.Mine shows where national parks and state forests are etc for areas to stay clear of etc.If i have missed anything, i'm happy to give more details only just touched the surface.