Thats hard because I've come to realize that even though I dont let Chloe outside too often (still a puppy) she LOVES it! I too would find it hard to constrain her, but for the time being I think the pen would be a good idea for two reasons. One, you know for sure you aren't going to lose your baby(unless she is a big digger
) and two, you know nothing is going to get her... if it has a top I mean. We have a hawk that lives on our street in the big trees... one can't be too careful with these little ones! Is she mostly an outside dog? Do you have a neighbor that is a close friend with a closed yard that she could run around in for her exersize a little everyday? Or perhaps getting a fairly long leash that is attatched to a pike that you hammer into the ground... then she can still run around and explore but the leash would not be long enough for her to get out of the yard. Anyways, just some ideas, good luck!!