I don't use a "trip planner". This works for me. To be honest, I haven't found a "trip planner" that I like. (Warning lengthy post... stop reading now if a lengthy post bothers you)
I have a Next Exit book, a Rand McNally trucker's atlas and a Rand McNally mid sized road atlas. I ripped the midsized atlas apart and it lives in sheet protectors in a 3 ring binder, just like the Next Exit does. I always have my daily route written down on paper.
To plan a trip, I use various websites, the Next Exit and the midsized atlas. I build and save the maps in Google My Maps. I will find a place/area to visit and build a map around that and save it for later. I prefer to find a "base" campground/RVpark and daytrip from that base. I have several "maps" saved in My Maps that I can build into a new trip.
Since I like to run US highways along with a few state and county roads, I use the trucker's atlas to make sure there isn't a problem with my route. Once I get my basic route marked out on the Mid sized atlas with wet erase markers (and this is why they are in sheet protectors), I double check my stops on Google satellite view to see where my best parking will be.
GasBuddy.com is good for finding fuel stops. Although I default to Sam's Clubs and Murphy's for fuel, particularly if overnight parking (ONP) in a Sam's Club lot (most of the time, not always, those two have the cheapest prices, unfortunately not all Sam's Clubs have diesel). I do unhook to get fuel as it's easier and I top off fuel either the night before or in the morning before heading out.
Once my trip is finalized, I plug it into the CoPilot. Each day is a trip. I have discovered that is easiest to work with. I have the (paid) CoPilot RV app on a dedicated tablet (VANKYO MatrixPad S7 7 inch Tablet). The tablet allows me to take the my GPS in my old towed or the truck camper or anything else I decide to drive. I tried the RV Trip Wizard trip planner and GPS app but it lost it's mind somewhere down the highway (Arkansas, I think). I find the CoPilot app easier to use.
For Daytripping, I use Onlyinyourstate.com to find places to visit and then pin them to one of the maps I saved in Google. For example, I recently read a book set in Charleston SC. So I have been looking at places to visit there. I like living museums, botanical gardens and food. So my map reflects those places that I find interesting. I also have several campgrounds/RVparks on that map. But no driving routes to/from my base as I'm not at that point. When I decide on a base, I will create a driving map, from my location to that base. Then the other POIs will be chosen. I can delete the POIs as I decide. Charleston is one of those places that will require multiple trips in order to see all the places I want to see. Plus I will be adding more places to the map as I find them. Along with where to get fuel while I'm there.