The advertised range between the RC and the drone is something like 2 miles I think. Definetely more than 2 km. After a few flights it seems that trees present a serious obstacle to this range. I do not expect to stay in control with a solid obstacle in between, and obviously many dense trees likewise. WHat has been the maximum range that you guys have operated at ? Was it only LOS that gave the long range?

To keep your VLOS, you might fly higher, keeping your drone well above the tree tops, and within your normal sight.  
If the connectivity gets blocked by obstacles, it may lose connection.  Flying in an open clear area will give the best connection, and help maintain line of site.

I have easily flown my Phantom 3 Pro' out a couple of kilometers. By using Lume Cubes has given me a much better and farther visual orientation.
http://www.lumecube.com/164.html
Not sure that this would be something that would interest you. As they aren't cheap... There are several other LED diode light kits on the market, that may interest you as well. ;-)


RedHotPoker

To answer your second to last question, I know a guy who flew a Phantom 19.4 miles away using his controller (it was not an autonomous mission).  So considerable range is possible if you're willing to go to the trouble, do the mods, learn the tricks of the trade, and find the perfect flying environment.  

http://www.flytrex.com/challenges/freestyle-distance/

can't wait to see how many flyway's this thread starts.....it's going to be good..

Think I will just read about it and not try it lol.