In regards to training ~ in Ontario we have Early Years for young families to take a part of a place free to get your babies out and meet other Moms ~ in my city they offer free daycare provider courses. See if you have something similar to that.
Yes you have been out of the business for a while being a Nanny a while ago but, the instinct and caring you have to get into this business doesn't go away. I know many providers who have all the training behind them and not the 'soft skills' to do the job and should get out!

If your feeling uncomfortable with some policies, listen to what your gut is telling you.
Starting up a daycare is tough...the first year of getting clients can be rough- we struggled a bit but it does get better as your reputation spreads through word of mouth. As you gain experience you can built on your website (webs.com is a great free site- ask the ladies what sites they use and you can check them out)
Good luck on your choice. Since you asked, I'll give you 3 cents worth and tell you that I wouldn't go with an agency either. This is your business and being able to control how things are run is the perk of the job Micro managed is something that doesn't suit me at all.
Good luck~ remember we are here to help if you need any suggestions, advice or as we all do, vent on those tough days