
No, you don't need to play with her constantly :)
You can use some (or all) of you play sessions with her, as training time. Fun, short sessions, really help with bonding, training and giving mental stimulation (helps elliviate boredom and the bad habbits born out of boredom such as chewing things they shouldn't).
Before my pup was allowed to go out for walks, I used to walk him around the garden on his lead, I wouldn't take a step if he pulled, but as soon as the lead was slack I would walk & he would get loads of praise or a treat. He found it great fun and it really helped with lead training (I probably looked like an idiot to the neighbours though!!!)
Playing with a toy/ball is a perfect opportunity to practice drop/give. All of the things you wish to teach her can be made into fun games that she will enjoy. It's suprising how quick they learn if you keep things fun and stop before they get bored. It does tire them out mentally too, so they are much more happy afterwards to play on thier own with a chew bone/sqeeky toy.
It's also great to get the kids envolved with teaching her, but they have to use the same commands as you do, or poor pup just ends up totally confused. My kids think its brilliant to be able to take the pup in the garden & practice sit, stay, come with him - it keeps the kids & the pup out of trouble :)