Hi Nelie,
I have one and I love it. We have these great hike and bike paths where I live and I wanted so badly to ride the bicycle on them. I borrowed my daughter's bicycle and was still in the driveway when I fell off
So I started looking into one of those 3 wheeled ones. I got mine on the Walmart web site ~ it was shipped to the store. They even assembled it for me at no charge. My son-in-law brought it home for me in his pick up. It can fold, but I've never tried that. I think you could ride it on a gravel path.
I've never regreted that purchase and continue to enjoy it.
Good luck in your search