Guidance and/or Recommendations Welcomed

Hello Forums,

I have been researching and researching and I have to say. I have falling for MikroTik and its RouterBoards. I have fallen for them so hard, I am dumping my Buffalo WZR-HP-AG300H. Before I make the jump, I want to try and get the board that I am using setup to best I can for home/WISP use. The WISP use will not be for reselling but for my own use in a small town. I do home/office visits and take with me a NetBook for troubleshooting or downloading drivers. Before I go much more in details on what my plans our with this setup, let me provide some info on what I have.

RB600A installed 6.0rc6 (Yes, I know it is EOL)
wlan1 - Ubiquiti SR2
wlan2 - Ubiquiti SR5 (disabled, plan to use for PTP station)
ether1 - WAN
ether 2 & 3 - Bridged
bridge1 - wlan1, ether 2 & 3

ether1 will be public facing so I need the most security that I can get on it. I have been victim of DDoS before and it sucks. (long story on that one)
bridge1 will server DHCP and NATed.

I do have a FTP server running locally.

Any tips or tricks that you may have or recommendations are greatly welcomed.

I have provided below some of what I have set for the Firewall > Filter

Flags: X - disabled, I - invalid, D - dynamic 
 0   ;;; allow internet connection to client
     chain=forward action=accept dst-address=192.168.0.0/24 in-interface=ether1 
     out-interface=bridge1 

 1   ;;; detect and drop port scan connections
     chain=input action=drop protocol=tcp psd=21,3s,3,1 in-interface=ether1 

 2   ;;; suppress DoS attack
     chain=input action=tarpit protocol=tcp src-address-list=black_list 
     in-interface=ether1 connection-limit=3,32 

 3   ;;; detect DoS attack
     chain=input action=add-src-to-address-list protocol=tcp 
     address-list=black_list address-list-timeout=1d in-interface=ether1 
     connection-limit=10,32 

 4   ;;; allow ICMP (Ping)
     chain=input action=accept protocol=icmp in-interface=ether1 

 5   ;;; allow DNS traffic
     chain=input action=accept protocol=udp in-interface=ether1 src-port=53

Here is the output of Firewall NAT

Flags: X - disabled, I - invalid, D - dynamic 
 0   ;;; pat outside
     chain=srcnat action=masquerade src-address=192.168.0.0/24 
     dst-address=0.0.0.0/0 out-interface=ether1 

 1 X ;;; Forward to 192.168.0.254
     chain=dstnat action=dst-nat to-addresses=192.168.0.254 to-ports=20-21 
     protocol=tcp dst-address=192.168.0.254 dst-port=20-21 

 2 X chain=dstnat action=dst-nat to-addresses=192.168.0.254 
     to-ports=50000-51000 protocol=tcp dst-address=192.168.0.254 
     dst-port=50000-51000 

 3 X chain=dstnat action=dst-nat to-addresses=192.168.0.254 to-ports=3389 
     protocol=tcp dst-address=192.168.0.254 dst-port=3389