To my knowledge (And according to Dale which perhaps just didn't elaborate because he could be sure someone else whould) its just (liberty) bells (produced by statesman-colonists in your Townhalls) which translate into ref-expansion.
Oh and you can get founding fathers without them allright. Just grab a master lumberjack + a carpenter or two early (any colonist turned lumberjack should provide 1 master carpenter if you can find a fitting spot to settle) and produce Politics-points with them. (Founding many colonies (like 8-10) and setting most of them to produce 3 politics Points each (thats the starting hammer for a settlement) each works as well and might! even be better. But thats if you like micromanagement since you have to manage all those colonies and play on epic or marathon to not lose many important turns from walking your settlers around. But playing epic is much reccomendable in my book anyways.)
Don't get bells / run statesmen without careful! preconsideration.
Also watch out that rebel sentiment is measured by colonists in settlements as well as! on guard-duty and outside of colonies.
Anything else right now seems completely unimportant with regards to the REF.
I completely pissed off the king (do i look as if i whould give him 6000 Gold in addition! to taxes?

Im not that

. Greedy

louis), have a huge population, bought quite many a gun + horse and have got 3 or 4 of the early founding Fathers (no wonder, i know Col 1 + read some forum before buying (got burned by spore hoax

) and play on a lower difficulty with the new game right now to get accustomed to it. Will move up two steps or 3 should i kick the REF's butt.) and the Ref is still about 20 Units in all. I could easily overbid that if i whould aim to.
Oh and if an AI player is pestering you with nearby culture and expanding borders:
Go over and take his belongings. Double win and AI doesn't seem to have a real clue (at least on lower difficulties.).
Or if you are French and don't have the capabilities go to the natives and ask them to kick those annoying spaniards / englishmans / dutchs butt for you. They will do so with ease.
If you heed this you might get a REF which you'll be able to handle.
If not you might find a story were yor beleagered pilgrims (

) of the Mayflower are faced with the army Napoleon marched into Russia instead of some friendly natives who gift them food on thanksgiving.
