Bridgeport CNC

I've been lurking for a while, and did some searching, but didn't find
quite what I was looking for.

I'm interested in putting together a CNC, and since I'm a farm kid,
probably need to do something bigger than a Taig etc. I have a friend
who has a Rong Fu that he likes, but I'm seeing old Bridgeport CNC's
that are either working or have bad electronics, so I'm currently
thinking of trying to find one of these production Bridgeports and
retrofit only the electronics. So the question to the group is - Is
this a dumb idea or a good way to go? Am I underestimating the
benchtop mills? Can I use the BP hardware, including servos and just
replace electronics or will I have to replace servos too? Any points
to links would be appreciated.

To muddy the waters a bit, I have a J head Bridgeport with DRO that I
suppose I could retro, but an additional machine - in a different
location would be fine - maybe even better.

And lastly, our high school has a round poled bench mill, with no DRO
etc. What would it cost me to convert to CNC and could I do CNC and
use it as DRO for hand jobs? Or should I start with something else -
budget tight at the school.

thanks a bunch