The recall sounds as if its going well. The idea behind a perfect recall is to never call the dog if its associated with something it doesn't want to do. When it's home time, never ever ever ever recall your dog, just walk up to her and put the lead on and head home/to the car. The same applies to bathtime or nailtrimming time. The art of a great recall is that the dog comes back because she knows its going to be better than what they are chasing after. Once you have her attention, she will no longer be thinking about what she was running to, the beauty of dogs with the inability to have anything other than a one track mind.

So, to strengthen your recall, make sure she gets lots of praise for coming back. A pat, a rub, a 'good girl' is just as much of a reward as the cheese you are using. Which, by the way, sounds like you are using too much, you'll need to start getting stingy with that cheese. A substitute of praise is just as much of a reward once you start weaning the dog off treats.

As for your dog's pooing habits, it sounds a lot like she is constipated to me and that she isn't getting the right stuff to break it up in her digestive system. I'm pretty sure that there's nothing wrong with her insides, probably just a lack of something in her diet. Try adding some fibre to it, along with the vegetables that sleeptalker suggested that will help break it up and allow her to get it all out in one go!

As for the park, you have to take into consideration that other dogs will leave their scent so that same blade of grass that you see her sniffing every day may look the same to you, to her, its a completely different blade of grass with a whole load of new stuff. She probably looks at your copy of Heat every week and thinks the same thing, lol "its the same paper, smells the same, looks the same, whats so different about it?", so theres no need to worry about the grass sniffing, its like a brand spanking new mag for her to read according to her nose.

As for the ball (and frisbee) games, the trick is to make sure that you are enjoying them. I look after a 16 year old border collie once every few months and her owner said she never chases the ball because she was too old. On her first walk, I managed to take a tennis ball, bounce up and down like a loony, wave it in front of her and she got very interested in it to the point that she was barking at me, I threw it and she growled at the thing the entire time she was running towards it.

Basically, if you don't get her in the mood to play fetch, theres a good possibility that she just simply won't be in the mood. Make wacky noises, pretend your 6 again and bounce around playfully, she should eventually join in and literally beg you to throw it. I'd also suggest alternating the toys, without knowing the breed, I can't really suggest an ideal game to play with her as different breeds were bred for different purposes. For example, you won't get many sniffer dogs playing fetch, just like you won't get many gundogs to play Sniff n Seek.

Another liklihood is that if the dog is used to getting treats after fetching and you are taking her out soon after a meal, the treat won't be as appetising to her if she is running on a full stomach. A hungry dog is an easy dog to train.