First of all, science penalty differs: on standard map 5%, on large map 3%. So ICS will be better the larger is map for sure.
real ICS - only through religion, sacred states and cultural victory. On the other hand, it is even more ICS that was in GNK. (I see now point to settle city on snow and empty see in GNK, for example) I suppose it is the fastest possible victory on deity on pangea.
There is another way, also with religion. You can take universities,public schools and laboratories for faith. University first costs 160 faith. This is ridicuosly small comparing to unit cost. So you should have not so bad cities and buy a lot of pagodas/cathedrals/... to get a lot of faith.