I agree that too much back and forth would be tedious (especially on something as large as it is).
currently, it sits at about 32 and a quarter diameter (with a garter border in cream color), though it may now be going into forced hibernation, as I ran out of this skein. so I probably have to wait at least until I can get more yarn (i think I had told my mom to buy two skeins of it)
shooting for 34 but may go for 36 (my mom is a fan of larger baby blankets; the other one I have on the needles is 34 inches wide and 27 inches long ;she told me to cast on 150 stitches for it, forgetting that I am a looser knitter than she is, that's how it ended up at 34 inches wide; it was kind of a joke, I saw her last and she measured it and I was like "thats your fault that its so big". )
not that a big blanket is a problem (in fact, if it weren't that its already on its 5th skein, I would consider going for 45 inches long and calling it a crib size blanket (or a personal sized throw blanket) .... )