Continent Study

Didn't get input from the homeschool group, so here's my situation and a question:

I'm trying to implement some Montessori into our school. I'd like to do a continent study in place of the map skills wkbk [which I've always used - 10yrs now]. How much time per week should they spend on this? How much time per continent do you spend? I know "it depends" - but what do you do? I'd just like specifics, I guess. Different activities within this study. Maybe some helpful blog/websites?

I just ordered Teach Me to Do It Myself from Amazon. Hopefully I'll get some great ideas for pre-school activities too.

Thanks in advance for any and all ideas, comments and well-wishes :o)