2cents worth for free,
think michigan is pretty much the same for cold as maine - so that
project for me, here would go like...
12" - 18" depth any less = no warrenty
bottom / sides of excavation covered in landscape fabric (not plastic
cheap stuff - fabric.)
drainage system out of aggregate to daylight / drywell.
21aa limestone aggregate to 2" shy of aggregate grade - tamped per 4"
cover with fabric.
you want to end up with a completly socked aggregate base.
builders sand to grade (bottom of slab) moisten before pour.
4" if no vehicle traffic is to be expected - 6" if so
6 bag fibre renforced concrete
use coated rebar if possible
CLOSED CELL POLY FOAM expansion joint material, not the oily stuff.
(example: http://www.apscork.com/apscork/closedcell.shtml )
smooth trowel finish
apply color(s) of choice in a court paint, like Duracourt Tennis Court
Paint, or equivalent. Stencils are available for correct markings if
good luck and have fun.
advise worth price charged