Need advice on an RV GPS?

I got a Garmin 2797LMT last year in preparation for our trip to California. I'm a hard-copy roadmap/do-lots-of-Google-maps-research-beforehand kinda guy and I was glad I kept that discipline. The Garmin was nice for some things especially locating gas stations, restaurants and such things up ahead. For route planning I think it sucks...it took us right through downtown Portland, OR during afternoon rushhour instead of routing us around town on the interstatevbypass. Another "failure" was as others noted, it sent us on a backroad that had been closed for months due to a bridge being washed out...and yes, I'd done all of the "updates" just before we left. Also, some gas stations had obviously been shuttered for years when we got to them. Bottom line is I don't trust or believe ANY GPS for accurate routing ALL of the time. It doesn't know if a road just flooded up ahead, and it sure as heck won't tell you that you can't get through a McDonald's driveway.