I bowled on a Pattern league this summer and Pattern 3 was the easiest by far for me.
It does seem pretty walled up. I had quite a bit of bounce room outside, and if you tugged it, it didn't kill you like Patterns 1 and 2. My best shot was to play over 12-15 at the arrows out to about 7, pretty deep down the lane. Unlike 2, 4 and 5, I didn't have to go direct.
Jess