I appreciate your way of looking at the numbers, but I think that if you are looking for a way to maximize the money here is what you are looking at:
Move= Saving $170/ month
Cost= 2 hours/day (2 people at 60 minutes round trip)*20 working days per month =40 hours of time (it may be more than that depending having to be early ready, not miss public transit, etc.)
this amounts to about $4.00/hour.
This also assumes that you never miss the bus and have to grab a cab, and that everything goes perfectly all the time. I know for me, I would pretty much be guaranteed to have at least a once a month "oops" where I would need to get somewhere in a hurry.
This also takes no account for the convenience of your current situation- of course, it is also does not take into account the neighborhoods- maybe the new place is cooler, etc.
My suggestions based on your info: you have limited time, and theoretically unlimited earnings potential. For such a small pay off, don't limit your time. If you have 40 hours a month to spare, then find a way to monetize it with a part time job close to home, or develop a new skill- easily worth $4.00/ hour even if you can't monetize it right now. Also, if you have been a good renter use the power of negotiation. It is possible that your landlord would happily negotiate a small deduction in rent for long term renters who take care of the place and always pay on time- this is not uncommon (although probably more so in SFran.)
Only you can decide what is right for you- but if are really serious about paying down those loans, I think that you could more likely find a part time job that would give you a much greater return.
Good luck whatever you choose!