Night/dark tips for T3i with pro flash?

I'm just getting back into photography after a hiatus of a number of years. I used to use film, and switched to digital a couple years ago when I got back into it. I was very limited on budget, so I opted for a cheaper body, preferring to save over time and sink money instead into better lenses and flashes. So what I have to work with:

Canon Rebel T3i
Canon Speedlite 600ex-rt
Canon EF 28mm f/2.8 IS
The standard and telephoto kit lenses--crappy slow, but it's all I have for other lenses. For now.
MeFOTO A2350Q2K Carbon Fiber tripod
MagicLantern (I've downloaded it, but haven't used it yet--should this help me at all)

I'm trying to do night shots---and by night, I mean pitch black darkness. Zero street lights. Forest cover. No city lights. It's an old, creepy backcountry road in southern Virginia.

Not surprisingly, automatic camera modes couldn't get an autofocus to take a shot. Even under manual, however, it was hit or miss--and mostly the latter. 9 times out of 10, even on manual, I couldn't get the shutter to fire.

I was hoping the powerful range of my flash would help light up the scenery I was trying to photograph in the dark.

What options do I have? How can I pull this off? I'm sure it's a limitation of my experience/technical skills--I've spent almost no time in low-light photography. (Ironic, too, considering my only formally licensed and published photos are of an ice cave in Alaska that was extreme low light--though I honestly don't know that I could re-create those once-in-a-lifetime shots.) But I figure it's also a limitation of my camera body, and maybe the lenses too.

In any event, the above is what I have to work with, the below is all I was able to muster, and I'm looking for some tips on how to consistently take photos in these kinds of conditions--using what I have to work with.

Any and all suggestions greatly appreciated. Here's a terrible photo, but one of the very few I could (seemingly randomly) get my camera to fire on, of what I was trying to photograph. I was attempting to shorten the range of the flash (in an effort to get more of the darkness in the background), hence the odd lighting cone.

And one more where it fired, but near fully lit the entire scene--also not my desired effect! I wanted to show the bridge in a backdrop of mostly darkness. That said, facing that specific angle of the bridge was the ONLY angle I could get any photo. I think it was that there was just a tiny bit of moonlight peeking through the forest cover at that general area, but I'm speculating.

And here's what it looks like during the day, for comparison. (Note: I wasn't there during the day and didn't take this photo; it's from Google Images so I have one to show, and I linked directly to the source, M. Barkley Photography):