You can say that again. I'm so far up the **** end of the world, no PvP could ever be fun. Even in ideal conditions, last mile ADSL routers (be glad it's not ISDN or PSTN) overheat in the summer, reboot every other minute, drop packets, etc.
I have no choice in the matter — ED will have to be single-player for me.
Not necessarily.
Of course the game can't do much if your internet itself is flaky, but one of the things coming relatively soon (tm) is geo-instancing and matchmaking. With that, you will be matched to people close to you geographically to help minimise ping times and latency. So, with luck, your game may not be held up by having to synchronise a player that's on the other side of the world to you.
Remember that the game is really being designed as a "play with your mates" kind of multiplayer, rather than an MMO in the traditional sense. The theory goes that your mates will live relatively close by.