There are a few sites that I use regularly when planning a road trip.
Roadside America has all kinds of roadside oddities, good stuff for road trips. For some reason, their phone app is not free.
Atlas Obscura lists all kinds of wonders and oddities all over the world, sortable by country or category.
Geocaching.com is great for finding out about an area even if you don’t geocache.
Roadtrippers.com has route planning and lots of places, odd places, tourist attractions, restaurants, all kinds of stuff.
MyScenicDrives shows scenic drives around the U.S.