I have a 13 month old, not really walking yet, and we're in the same situation. To make matters worse, he has a 3 yr old brother who is running around doing EVERYTHING and baby certainly wouldn't tolerate a play yard.
I've tried our walker on the grass. Doesn't work. SO if you try the walker, use the driveway. When my older son was at that stage, I actively encouraged the use of a pacifier figuring if he had the binky in his mouth, he wouldn't be putting other stuff in his mouth, but that just led to a bad pacifier habit, so we aren't repeating that mistake with the baby.
Some things that do work for us: I lug him around in a wagon. This occupies him for a bit, until he tries to climb out or I get tired. We have one of those plastic mini-playsets, with a small ladder and a ramp, and I let him climb around on that (assisted, of course). We also have one of those plastic little tykes log cabins, and he adores "walking" around that from window to window and playing peek-a-boo out the windows. The 3 yr old still likes the house too, but the 3 yr old doesn't care about the playset, so I'd say the little house is a better investment.
I have given up on getting yard work done for a few years. (Which, hee hee, is fine with me!)