the surface2 and surface2 pro have one usb3 port each, the surface pro / surface RT one regular usb port. both generations also support bluetooth.
those are well suited for serial i/o.
an extenal gps "bug" or "mouse" is imho a better choice for flying than most tablet internal gps chips, although the internal ones have improved greatly in the last few years.
as to software, just take note that for this kind of application only the "pro" surfaces will work as they allow custom software and drivers to be installed / intel platform being backwards compatible. windows RT will only run apps from the store ecosystem and which were built for windows 8 with code both for arm as well as x86 processor technology.
that is not to discount the RT surface tablets, which can be a great value, especially with office included. just not for flying/navigation.
check out "EasyVFR" from
www.pocketfms.com
also works in north america and pretty much all the important aviation markets. as a plus, you can export the map data also to be used for the mapping in advanced flight systems, dynon and mgl efis's.