When doing the Nuclear Option quest:

I got all the way through the tunnels into the Institute. I shoved the tape into the terminal, and thinking this was going to start a countdown sequence to blow the place up, I gated back to Sanctuary. I then discovered I was supposed to meet Preston Sturges INSIDE the Institute. But at that point, the game wouldn't let me teleport ANYWHERE. (I got the "You cannot teleport from this location" message, even at Sanctuary.) So Nick and I hoofed it all the way back to the tunnels, went back in and down, got back to the tunnel leading to the Institute ... but couldn't get in. There's no option to open the hatch in the tunnel to get back inside. It's just closed.

I've loaded up previous saves and quick saves to try and return to a prior point (even one I'm pretty sure was created before I started this quest), but each time the game is stuck in the same place: No teleporting anywhere on the map, and no getting back into the Institute. And right now, I'm at a point where I can neither get into the Institute nor leave the maintenance area, because there's no way to get back up that waterfall that got you inside.

I've got one save I can try that was logged a full 27 hours earlier, but ... wow. That's a lot of game to lose.

Unless there's a patch for this, the game's effectively over for me. I don't want to dial the game back that far and I can't even be certain it's going to solve the problem.