The 3 wheel Pet Gear NV is great on rough terrain. You are correct it is expensive though. The best price I found on it was @ Drs Foster & Smith.
I wore the wheels off (or they broke) of two other strollers that had hard wheels on them. But then I run with it so it gets used fairly hard and we got parks and such. Guess we use it a lot. It is large so she can have a friend along too.
__________________ .  Cali  , and Cali's keeper and staff, Jay No, not a "mini" Yorkie - She loves to motor in her Mini Cooper car |