Tried a G. washington game with full commerce focus, terra on standard. Only normal game speed. Will try epic now.
Preliminary test results:
Old world
-Worked well, and migrated to other continent in around 1200AD with only 3 cities in old world.
-Got closed in quickly, so building settlers early is needed. Low sea level would help to create more land.
-An aggressive neighour, like Monty for me, declared a little early which hampered my commerce effort.
-Workers chopped all forest in range to make up for the lack of production tiles.
-Was able to make quite a bit of money from trades.
-I built Colossus which helped commerce, but also gave me a great merchant!

-You can only gift cities to direct neighbours.
New world
-Whipped old cities down to size one, let montezuma take it and presto, the capital moved to the other side of the world. I left a few units to pillage the fully developed towns.
-Brought a few settlers, but didnt really need them as there were many barbarian settlements.
-Brought workers to new continent, which really helped.
-Most important was to bring a good sized army to take all the barb cities.
Will report more from the epic test.