I've been working on training Lola (15wks) to retrieve.  I first started in the house then moved to our small fenced back yard.  She retrieves extremely well in the contained environment. However when I take her to the park in our neighborhood she loses all interest (like she's got add).  I'm guessing the curiousity of the open space is overwhelming for her at this age and that is causing the loss of interest.  Anyone have any tips as to how to get her to focus and increase the drive to retrieve?

Relax, she is just a puppy.  Let her have some fun.  She will get their.  Just keep playing retrieve with her in the contained area, and take her to the park for play time.  She will get used to the park and eventually will do retrieves just fine in the park and other areas.

I don't hunt my GSPs, but I do train and show in obedience.  Each one of my three have been different in the retrieving arena.  In the early stages (before I teach a forced retrieve with the dumbell for Open) I make it a play game.  Each of mine has responded differently.  My oldest learned to retrieve easily, but was about 4 - 5 months when we started her retrieving.  Halo, my number 2 furkid, didn't learn a good retrieve until she was about 1.5 years old.  She wanted to play keep away. Between Belle and Halo, Halo is much stronger now in retrieving and returning.  Most of that came after I taught her the forced retrieve witht he dumbell.

My new kid, Ringo, who is 3 mos started retrieving as soon as we brought him home at 8 weeks.  I found out by accident as I was playing with a ball with him and he ran and got it and brought it back.  We do this all the time now. 

I never reward the retrieve with food, just lots of praise.  I also make the retrieve a game with my dogs.  If they do what I want the game continues, if not game over.  That worked really well with Halo when she wanted to play keep away.  I never chased my dogs when we were doing retrieve as that just reinforces the bad behavior. 

I would just keep playing with your pup and eventually he will start showing interest (just keep is short and fun, don't make it too much like work).  I have yet to see a GSP that didn't like to retrieve.

I feel your pain, but you are right they are worth it a million times over.  That is why I have 3 GSPs now.

Congratulations.  GSPs are great retrievers on land and in water.  Have fun!!z