I'll share my
interesting experience where I was saved by my Swiss Army penknife.
Riding South from Bwlch-y-Groes I turned off at Nant-yr-Onog on to a permissive path. A horrible path, as it happens, with deep rutted mud and wind-blown branches between deep banks. In short, a push. I breathed a sigh of relief when it passed into some forestry and flattened out. Not for long though, because the trees had been knocked down across the track meaning I had to climb the very steep bank to get around them.
It doesn't look steep in the photo but the only way to do it was to first get a firm footing, then push the bike up a foot or so, apply the rear brake and then repeat. Going down and around was not an option because of the 20-30ft drop into a rocky valley with a river in it. So having got above, I could see another tree-jam and another after that, but unless I could detour much much higher I was still stuck because the bank had slipped leaving a deep, steep, loose valley to get down then back up again. I got back down to the track could see that the trunks had bridged across leaving a gap below, but this was closed by branches wedged into the ground.
Sorry about the picture but the camera lens was steamed up. What looks like a field above the obvious trunk is another, bigger tree trunk. Nowt else for it but to bring out the SAK and start sawing, eventually making a hole big enough to drag the bike through on its side. Phew!
I had to do this twice, but then it became possible to get down to the river and wade upstream for a hundred yards or so before pushing up another, this time soggy boggy mossy steep bank to a track. The sun had come out by this time and when, after a couple of hundred yards or so I took off my waterproofs, I thought I'd left my phone down
there somewhere.

"There's no way I'm going back down there" I thought, "I'll just have to buy a new phone". Then I remembered I'd put it in another pocket.
So all this faffing about took me at least an hour to get 200 yards. Type Two fun this,and no mistake.