@littlek,
I agree with you littleK.
Part of balancing my checkbook is to keep track of which checks are outstanding. After that, it is not difficult to subtract the amount of checks outstanding from my current balance to find out if I have enough money for whatever.
Factually, I prefer you not cash my checks right away. By not cashing my checks you are letting me keep the money a bit longer... meaning I get to at least make interest on it.
But in either case, two weeks is almost nothing.
Maybe your friend could pay you with PayPal or a money order (either of which would take the money out of her account right away as she wants)-- or she could just give you cash.