In the Tower in Old Town Savvy gives you this quest to clear the radio station outpost that was taken by Rais.
The Outpost for this quest is the one farther south - access to basically unrelated areas can be had from on the roof through a push-door. Those are worth exploring so you can loot what loot is there - some of it is nice.
The actual access to the Station is down at around ground level - but this IS an Outpost and it HAS been fortified, so you want to go easy and not attract any attention to yourself as you are making your way inside.
At the ground level in the cut in area by the white van you can kick in the boards blocking off acces to the fenced in area in front but be discrete. There are regular infected here - and you may need to deal with any that notice you enter that way.
Follow the barricaded path to the center of the side and you will see that you can get to the door that triggers the Radio Station Instance.
Once inside bear in mind that you are dealing with Rais' men but also that you ARE inside - which means it is safer (but not totally safe) to use firearms. Let me repeat that - you are now INSIDE an Instance. You CAN use firearms here with relative safety. Just saying.
Inside you will enter an atrium like area - you need to climb up to the scaffolding and then drop down to go in through the window before you can start to clear the area of Rais' men. There are security cameras inside - take them out, don't take them out, it is your call.
I faced a squad of twelve enemy on the first floor, and another twelve on the second. The guys on the second floor were the same tactics wise as those on the first until the third set at the rear of the area, as those ones started throwing Molotov Cocktails.
Once you finish off the third group on the second floor that is it - you have cleared the Outpost. There is a lift at the back of this area that you can use to get to Old Town - so you do not need to retrace your steps.
Before you go though, check the time - make sure you are not heading out into the night! Before you leave do not neglect to restock your rifle ammunition from the bodies - and there are two Disaster Relief Packages from one of the Air Drops here - be sure you grab them.