tl;dr further down
First off let me just ask why I have not heard of MikroTik before last week ?? Wow, it seems so amazing - almost too good to be true. The amount of features you get for the money, and the amount of horsepower you get aswell from the routerboard products. Not only that, skimming through the forums it seems like there are so many experienced users with 1000+ posts helping and even being patient with the “lesser” technical people who barely describe their problem. Great to see! 
So, my situation is that I am seriously considering replacing our ISA 2003 servers in our branches with some other solution, after finding out about MikroTik it may very well be the RB450G. The main purpose of our ISA 2003 is used to deny access to everything on WAN, except the websites that we allow - and to interconnect the branches via. VPN.
I will probably use this thread for my basic questions so I don’t have to recreate one every single time but for the time being, here are my 2 questions for now:
tl;dr
How would I go about denying access to all websites except the one’s I have allowed? What are the possibilities here? I have tried the Web Proxy but it does not seem like I can make it work the way I am thinking - where everything gets blocked except sites I define.
*I got this solved by playing around with the web proxy rules. I just needed a deny all at the bottom and for example google.com allow above.
What method would you suggest on connecting the branches so that 192.168.12.10/24 can ping 192.168.13.10/24?
I got this solved with IPsec site to site http://wiki.mikrotik.com/wiki/Manual:IP/IPsec#Site_to_Site_IpSec_Tunnel
Ok so far I got my own answers but will use the thread in the future if some other help is required, thanks anyways