I spent the last 2 nights climbing a mountain in a BeamNG Drive user made map. This particular map is old enough that you had to find a patch to fix all the textures, because it referenced older textures that were taken out of the game and it was never updated.
Anyway, my weapon was the little truck that they put into the last update. There are much better mountain climbing vehicles in the game that aren't as top heavy and have better boulder clearance but I decided to go with this because I like how it looks.
I spent many hours making very slow progress. I had the truck in it's lowest gear setting and with both axles locked, and never getting out of 2nd gear. Lots of hill starts. lots of sections where I'd have to get a head of steam to get over some of the more brutal inclines. Due to the map's size and the extreme topography of the terrain I was sometimes straddling individual polygons that made up the ground. There were moments where I was stuck at redline for a long time and spinning all the tires on like a 50 degree angle. Progress could come in fits and starts.
Anyway, I made it to the top and I only had to cheat past 3 sections.