So, I don't really have much experience with Travelling Fair, certainly with Gardens, but I don't expect it's a great enabler. You usually don't have so much extra money to throw around, and top-decking is not as good when you're getting to buying green fast. Still, of course I am sure it helps sometimes.
The question about CSM is a bit interesting. I certainly don't think it's a great "enabler", though it's ok. I mean, there tend to be a couple ways you can play Gardens: as some points while you're running piles out really fast (rush), or as a way to get a huge mass of points that can't really be overcome (slog). I suppose you want CSM for a rush more than a slog? The issue is that the economic impact just isn't all that huge - they're effectively coppers with buys attached. And while the tokens can be nice, once you have so many CSM, the marginal utility of the money being in token form goes way down. And it still takes a loooooong time for you to be able to pile CSM+Gardens+Estate (I am guessing that's the third pile usually). Or maybe you're playing it as a slog, but I think the mediocre economy hurts even worse there.
In addition to Beggar and Ironworks, I assume at least Squire, off the top of my head, is a better enabler.