To me, 'established' means that they possess all or most of the following qualities: 1) Have a website, 2) Have active ads on venues other than BP, 3) Seem intelligent in their presentation and correspondence, 4) Seem like they give a sh** about who they see, i.e. have some standards, 5) Have reviews, 6) Have been around for more than a few months, and 7) Are not known for lax screening, drug use, or other risky activities.
If a reference has all - or at least, say, 4 of 7 - then I'll contact her. Whether or not I accept the reference depends upon the vibe I get, though. Some girls don't screen... some girls accept behaviors from clients I wouldn't... some girls can't even remember if they saw the guy or not. They'll say, 'Well, doesn't ring a bell, but if he did anything bad to me I'd remember.' Plus, I'm always surprised how many women have seen guys I'd personally think *nobody* would, like, EVER see.
I don't recommend asking to meet for coffee (or a drink) as a way to make her feel more comfortable. To me, it comes across as a way to avoid screening... or, if you don't make it clear that you understand that the time is compensated, I'll feel like you don't value my time/business. I mean, how much time am I expected to spend with you until you feel comfortable? An hour, or even two or more? And that's in addition to the BCD time? That can easily turn into a whole evening spent, and I'd hope you're not just thinking it's OK to pay for one hour after taking up my whole afternoon or evening.
It also kind of screams timewaster. I personally travel to all of my dates, so I incur travel costs (tolls, gas, parking). That's in addition to the time and money it takes for me to be date-ready (hair professionally blown out, fresh mani/pedi, etc.). So when a guy tells me he wants to meet "for coffee" and then "hopefully"... I'll usually tell him that he needs to commit, or choose another lady..