Hi Lou, well done on starting a gym log. You're right, exercise doesn't have to be done at the gym. And having pushed Georgia (who is still tiny) into town the other day - it made quite a significant different to how easy the walk was, so if you're pushing your two I'd say you're getting some good exercise.
I own an abs cradle, but I am so lazy using it. I must go and do a minute everytime I see it or think about it - especially since my belly is my number one bad area!
Enjoy the gardening, Jay