I agree, the Garmin must have some sort of kickback from vendors along the route, they sure take you out of the way sometimes to get between point A and B!
This last trip, I used two apps to keep me going the correct direction. One was my Garmin ( I think an RV785) that I loaded with a route through their PC based software called basecamp. If you haven't used it, plan on spending some maybe not so quality time trying to learn how to get that program to take you the way you want to go.
the other app was the smart phone based version of the RV Travel Wizard ( BTW, they sponsor this web site).
Their web based app will let you choose RV or not route, speed, and how far you want to drive per day in hours or miles. The web based app will draw a ring on the map, that represents the approximate time or distance you would travel from your starting spot or last place you stopped. I thought this was quite handy for choosing a place to stop for the night. The phone based app pretty much just shows you the route that you set up in the Web based software. It wasn't 100% perfect, and I don't think any of them are. The RV Wizard used to have a 30 day trial period before they would ask you to buy it. If your a member of the Escapees RV group, I think it's 3 months free and a reduced rate to purchase the year subscription. No I don't get any reimbursement from RV Life or RV Wizard for telling you this.
One poster suggested another app to "put on you pad". If he means smart phone then, sure try it. If he really means pad, like iPad, its good to know that only the iPads with built in cell service have the built in GPS, standard iPads don't have GPS,
Best of luck with your choices.
2021 Ram 3500 HO CC LB 4WD Tradehorn
2017 Arctic Fox 25W
HAM guy (Ke7FIX), Retired Robotics Technician, USAF