Matthew,
Having just done a similar trip, I know you'll have an excellent time. Best of luck to you with logistics and everything in your future, too.
It sounds like you'll get in at least two rounds on the Old Course? That's terrific, and I hope you'll have the time and energy for a few more, even if it means playing as a single.
Also, I'd like to echo Jaeger's comments about North Berwick--I think you'll really enjoy seeing the course twice.
Look forward to comparing notes.
Best,
JB