[...] and there may just be no way from here to what you want with that unit. -- Seems more like "no method"
There's no way from here - here meaning 'the present situation' - to what the person wants the outcome, or new, changed, situation to be. To my mind this means that, having thought through possible steps to move from one state to another, the speaker has concluded that there are no workable options. So, 'no viable series of steps from a to b exists' is the meaning, I think.
I was hoping to see the locked check box here (as it is now in control of the client) - but I poked around and found no way from here to do it. I suppose if I manually changed the registry it would work -- Seems more like "no method"
Yes, no method I think, there isn't a remote way for the speaker to unlock the check box, as the client has control. So 'from here' is the speaker's PC, he can't unlock the box from his PC because there is no available method for him to do so.
Since there's no way from here over the mountains to Nant Gefalion we have to go up the track from Derwen. -- Seems more like "no road from here"
Yes, more straightforward, no road (or path/route) from where they are at the moment.
Reminds me of a related anecdote I've heard a few times - 'you can't get there from here' - it goes like this: A stranger is trying to get to a particular place. Lost, he asks a local 'how do I get to X?'. The local replies, well, you can't get there from here' - meaning that in order to reach X, the stranger would need to go right back to another point in his journey and take an entirely different route.