Forget about the tech tree until your mines and portal are upgraded, there are various conversations about the numbers of granite and copper mines needed but I went with upgrading everything to lvl 4 before working on the tree again.
Every guest race is slow, but if they were any faster then more people will end up at the end of the game before the next chapter is released.
I have one city in woodelves and one in dwarves and there are pros and cons for both of them, yes the one in dwarves doesn't need to wait between guest races as there are another 3 before reaching the end of the last chapter but equally the AWs aren't being levelled as fast because there is no pausing between chapters.