Could land dwelling dinosaurs climb hills? Small grades I’m sure, but steeper hills?
Just curious…
Sure, why not? Elephants and rhinos can.
You are aware that there are many types of dinosaurs aren’t you? Some could climb steep grades and others could not. Some could just fly up to the top.
And still can! 
There were lots of small dinosaurs that were very agile, including some that may have climbed trees (even non-avian dinosaurs).
Since elephants can be found high on the slopes of mountains in Africa, no doubt even some larger dinosaurs could negotiate fairly steep terrain.
However, most fossil-bearing sediments are formed in lowland environments. It would be rare for mountain-dwelling dinosaurs to be fossilized.