Anyone know if they have this type of information locked away, especially for low overpass/bridge information? If so, I can't find it. Thanks.

They “may” have it somewhere, but if you really need accurate information you should contact the State DOTs since they maintain this data.

RV folks should be a resource for recommended products.
No personal experience with this product. (my vehicle is 58.1")
Low clearances POI

Can't you just get on Channel 19 and ask for a Smokey report?

Have you checked out Rand McNally's RVGPS app?

https://www.noobie.com/2013/06...-low-bridge-heights/

ETA: I guess it's not an app but a snandalone GPS device.

Doubtful, but I'd recommend a Garmin Dezl.

They are quite accurate, and offer settings for height, length, width, gvw, number of trailers, axle weight, and more.

I use a Garmin 425LMT professionally.

I agree with the Garmin. My old Nuvi has settings for trucks. I use it when I tow my RV.

There's a Garmin RV specific GPS and the Rand-McNally one. Otherwise, you need the Rand-McNally Motor Carrier's Atlas. No information on any of the online mapping providers. You try to check each state, but the information may or may not be available.

In Florida, after having gone down a road that had and 8' clearance sign with our 11'6" travel trailer, I tried to find an online resource that I could use to find the information while planning ahead of time and came up with nothing searching for the name of the road itself. The sign wasn't visible until after I had made the turn and there were cars behind me.
These are the roads and I couldn't find anywhere online that losted them:
Old Dixie Hwy - 12' clearance and an actual exit off I-95, would have been nice to know before we exited.
Walter Boardman Ln - 8' clearance
High Bridge Rd. - 8' clearance