I'm sure mistermike, whomever he may be, will respons to you but i thought his post was so good that i thought i'd help elucidate.
I large hide area (maybe a board or plastic box top) is a good idea as are the following cheap, easy to grow and edible (for turtles) plants:
elodea/anacharis there is a bunch of related planyts that go by these names all are good and eay (though some are illegal in some areas as they grow so eaily they are pest species)you can but it at most pet stores that sell lots of tropical fish or many pond stores. if you need a source, message me.
elodea
water lettuce also cheap but more than the above two, but spreads over a pond surface much faster. can be hard to get if you don't order itt from apond or aquarium supplier (again if you need a s source, ask)
waterlettuce
duckeweed tiny and usually sold by the quart or pound, its spread fast in strong light and turtles eat it it makes for a darker pond bottom easy to get anywhere they have water lettuce
duckweed
other plants i'd reccomend if you can find them are water hyacinth, salvinia and ludwigia.
A good source for all of these (they ship) is azwatergardens
as far as fish go
not tomay will live long in a pool outside in the summer unless you have some areation in the water
if you have no plans for a filter ot air pump then i'd say ditch the fish
if you are willing to get one let me know and i can suggest some fish species
-rob