New to allstar and would like to learn about "remote base" operation

I currently have all the “makings” for a 6 meter base station;
an almost (new old stock) GE Master II 40 watt mobile, 2 channel
52.525 and a local repeater.
a short cable that would go to the control head ( no control
a nice 20 amp power supply and any number of raspberry pi’s.
my “original” plan was to connect the pi’s together via the
internet, and put the
remote base at a friends house, but he moved. I was told that I
was trying to
"re-invent the wheel and that putting up an alstar node would be
easier …
the first two questions, can one build there own radio interface
? and along those lines
is there anything in the software to allow changing channels (
only two channels )

Don, K8ZGW Twinsburg Ohio