I think you're heading in the right direction. A friend purchased a GIANT ROAM about 2 years ago. A step up from his WalMarts bike. He really likes it. Goes biking-camping on it. Un loaded touring.
You'll have to decide if you want a suspension for or not. I, personally, do not think they are needed for dirt road riding or commuting. But if you don't care about a small weight increase for a suspension for, AND it gets you out on the bike, then it's a good thing.
Talk to your Local Bike Shop about weight limits for the frame you buy. I think , don't know for sure, at 250lbs, you might be at a point of concern. I think the next point is like 180 or 190.
And don't be afraid of a used bike. You might be able to get more bike and more stuff for less cash.
I'm half way through this book, which seems like a really good starting place for folks who haven't been on a bike in a while:
https://www.amazon.com/Ultimate-Bicy...l&tag=bsn04-20