QC: You have to jump everywhere you go to get those glitches to happen, which I end to do because it's a little faster than walking early on. Getting stuck though happens when you get impatient, climb over the mountains and then race about like the game doesn't have anyway to stop you anymore. As for falling through the world, it happens, you just have to provoke it, but it's possible in most indoor areas. Vivec and the very first building of the game (especially on the stairs) are where this is the worst in my experience.
StingingVelvet: Not saying they never happen, just putting it in perspective.
I know. I sometimes have trouble getting those glitches to happen to, Vivec's the easiest place to get the glitch to happen, the lower levels especially if you want to try it. Thankfully it lets you swim out of the buildings, but I remember one time where I wound up jumping through about 3 or 4 times in a row, got frustrated and started jumping along the guard rails instead whenever I visited.
I do still love this game though. Now if only I didn't have to turn all of Syda Neen into my personal storage facility, I literally use half the town and can spend an hour at a time stacking together my items and re-organizing them after a nice long session of killing selling and collecting.
pi4t: Personally, I started without mods, and on the occasions where I felt something was missing from the game, I installed them. One mod I personally did install, though, was
Living Cities of Vvardenfell, which puts npcs in different locations depending on the time of day. It's not ideal, as due to the engine not really being designed for that they teleport to their new locations suddenly rather than moving over there, but for me I found it added to the verisimilitude a lot. I'd suggest trying without, though, and then deciding, as it breaks savegames if you uninstall it.
pi4t: I just thought I should point out that if you get stuck on a hill, and don't yet have levitation, you don't have to reload (in the vast majority of situations). You can just type fixme into the console (which is accessed like in later games with the ` key, in the top left corner of most keyboards), which will teleport you a short distance from your current location, hopefully freeing you from the rock.
I just wish Oblivion could do that. I've had to reload it far more times than Morrowind due to being trapped.
Also, they're called 'Silt Striders', not 'Silt Riders'!
I'm doing this all from memory, so you can't blame me for getting something wrong here and there. Last time I played was......... 4 months ago? I kinda wish I knew I could just type that though (I did already know about accessing that scripting though), it would have saved me from restarting more than a couple characters.