I haven't got close to researching Radio in any of my attempts yet.
Oxford I normally use for archaeology.
Tech path on my fastest game was fubared. I finished liberty early, I think to get a GA to settle, though possibly it was a GE for Petra. I used the 4 free culture buildings for ampitheatres, I forgot that hermitage needs its own tech. But that meant waiting at least 2 extra policies to open up piety, and all that bonus happy culture/cheaper policies. Also, finishing tradition and popping a great person when your capital is at 148/150 for a GA causes you to wonder where the GA you were supposed to get next turn has gone, and discover it's now at 151/300.

Joys of learning the game, this month is the first time I've played in well over a year.
Culture path now seems to go tradition open --> liberty open --> production --> free settler --> free worker --> liberty golden age (unless piety is available) --> piety x 5, fill liberty, fill tradition (both subject to holding off until i can get 4 free opera houses/or because a GA is about to pop) --> freedom open & finished ASAP --> whatever's left. Hard to decide between commerce/patronage as 5th. Commerce is more culture from the bonus happiness, but I think patronage is more science.
My first spain game (4 cities, 1 CS and 3 AI puppet cities), I didn't register how much bonus culture there was from a golden age. Planted lots of GAs. Second Spain game (4 cities, completely peaceful, not even a stolen worker) I had a constant GA for the last 100+ turns, I think. But not enough planted.
Biggest thing slowing me is lack of science, I think. I've managed to steal Bronze Working via my spy on at least one occasion.

Might be better off detouring my research path in order to get aqueducts much earlier, even though it means building/buying them myself.