Let me give this:
After I got the mechanics of the game down and such, I started to head father in the mainland. I've only ever gone farther in solo because Snivy and the others always were to far from me to bother.
My tactic was to follow a road heading north and hit a few cities. For me, to reach all the way to the NW Airfield, it took about 2hrs, with a little bit of a detour due to bad direction. With the cities I hit on the way, I got extremely nice supplies. However, the three times I've gone to the NW Airfield, I've ended up dying.
The first time was a brand new experience for me. I wasn't fully aware that people would camp there forever. When I go to the edge of the Airfield getting to enter in, I see a dude. We end up finding out we're friendly and start to walk in. The moment we step out of the forest line, this dude get's taken out by a sniper. I start sprinting off in the opposite direction and miss like four or five shots. I really wanted to get this guy, so I started to walk around the long way so I could flank him. I get lucky like three more times with him missing shots before he finally gets me. Not wanting to give this guy my gear, I force close once he makes me pass out and bleed out in another server.
The second time was by a zombie. Of course at first, I was able to get revived by Sanders and Snivy. However, it turns out an hour or so later, my character didn't save. So when I rejoin, I'm back to where I was when I was bleeding to death.
The third time I was extremely more careful. I went around the whole forest line to make sure there weren't any snipers hiding there. Once I finished, I started crawling into each hanger. Once I reach the watch tower, I alert the horde and head to the top. Up there, I find a survivor who has killed a bandit. I tell him I'm friendly and all is good. We start killing the zeds who come up and all until he decides to throw a nade down below. I wasn't aware it was a grenade until I was dead...
So yeah, moral of the story, you'll more than likely die at the NW Airfield.
If you get too attached to your stuff beware, you face:
RIGHT WHEN YOU LEAST EXPECT IT
Yeah, I've spent majority of my time playing this game walking all the way up to NW Airfield and dying there. It is annoying as hell. I've learned to just avoid it and head back down to the coast once I've gotten decent supplies.