I would just keep booking and booking, at least to the end of the next season, starting as Heath said, when theaters announce their next year’s shows. For AEA you want to keep in mind where you are with weeks for health insurance, which may lead to times when a longer run at a lower wage is more valuable than the opposite. When I feel like my 12-20 weeks are covered, I don’t worry too much about gaps between shows. They are a nice time to recharge, plus you have the option to take unemployment, temp, or do some other sideline work. Gaps also leave you open to the possibility of take-overs and other short-term show positions. As for better jobs that come up for times you are already booked, you can always withdraw from the original if that would be the best business decision (think of it as providing an opportunity to another SM).
Interestingly, when I was non-equity, I felt that it was better not to book as far in advance. At least in the DC area, it seems like good gigs would come up closer to their start dates. And the lower the pay, the worse I would feel about backing out since I knew it was hard to find good people for those jobs.