the boredom mainly...

For the mother type friend that comes up...you can always try a backhanded compliment with a smile, or something I like to use, "woah lady! quit screaming at me, your friend just wanted to look at my dog..." say it with a coyish smile and a little bit of cockyness, just don't over do it, and a little sarcasm helps too....something else you can do is once the friend comes over, engage her in conversation, get her talking to you in a friendly manner and you can probably get them both to hang around long enough to snag a number...

as far as taking your dog to another park...the world is your park man...go where you please...if the girl who invited you isn't there...sounds like you have no problem meeting new women so...run with it...hope this helps man.