I'm interested in joining.

A mix between all three types can be fine, if you feel the difficulty is too easy, you could always bump up the size and frequency of the biters.

Personally, it should be all three types, but I would like more emphasis on the towns.

For mods, I have just started under Bob's Mods, so I don't have ...

I will be down to multiplayer, but it will also be the first time as well. I have yet to play extensively into mods, but I have some decent experience with vanilla so it shouldn't be too difficult to learn some of the mods.