Why? 
The rule of the thumb (for beginners) is to leave the OS as is (and anyway ask before upgrading).
The menu “wireless” is now “wi-fi”, depending on which version and drivers you have installed.
It is confusing:
https://help.mikrotik.com/docs/display/ROS/Wireless
Check what you have installed, you want the “old” drivers:
routeros + wireless
since you are using the w60G interface.
The SA is usually used for PtMP setup, if you have only two devices PtP, two Cubes Pro (not SA) would have been more suitable (and there is a version with two units substantially pre-configured and pre-coupled, called “wireless wire”), but at 75 feet distance there should be no issues.
Coincidentally, there is another member who is setting up a similar connection, this thread might give you some inspiration:
http://forum.mikrotik.com/t/connecting-3-locations-beginner-here/177495/1
Since you are running a latest 7.15.3 there may be some changes needed, if I were you I would seriously consider the idea of downgrading to the “long term release” 6.49.13.