The first picture shows a track that is perfectly easy to ride across as long as you keep away from the gap in the ties. That just requires you to take the proper line and watch where you are going

The second picture is more problematic but not undoable. It's hardly any rougher than you'd find on just about any 10 feet or so of mountain bike trail. I'd probably pick a line that was to the right or left where the tire is so that I'd wouldn't be riding right across the worst of the hole. I don't think I'd even have a problem riding a fully loaded touring bike over that.

Mountain biking really helps in learning bike handling skills. Once you been down a trail full of baby heads, everything else is easy