I am a foreclosure Paralegal, and I can tell you that Short Sale is the better option before foreclosure. The impact of the Short Sale on your credit depends on the lenght of the deliquency of the mortgage payments, and also how badly upside-down the property is. Basically, if payments are current, you can negotiate the Short Sale to be contingent on a waiver of deficiency (which means the bank will take whatever is made from the sale and not come after your for the difference), but if you obtain the waiver and a short sale approval while having been current, there will be no damage to your credit. I live in South Florida, and from the hundreds of cases I've handled, I can tell you the banks have not been very open to consider a short sale if the homeowner is current with their payment, and people usually have to go 90 days delinquent to get the bank motivated to consider loss mitigation options.
I would try not to go over 90 days delinquent and seeks a short sale approval with a waiver of defiency. Also, please remember that whatever the shortfall is, they will most likely give you a 1099 for it before next tax seasons. We had clients short sale for 70k under the amount owed, and they have all been slapped with 1099's these past few months.
We are in similar situations, only that I don't have children but I do care for an elderly mom with health issues and no financial assistance, because she is a foreign national. I have been lucky enough to have saved up some money which I know will come handy, but no matter what I will get myself into an abyss of debt. By all calculations, I'll be applying to medschools when I'm 36. I know the HSPS military scholarship has an age cutoff of 36, but they also grant age waivers to the right applicants, so if you are fit and feel like you can enter into that deep commitment for your country, it sould be an option, as they pay your full Tuition, Fees and book + a monthly stipend of about $2k. You will serve one year active duty for every year of the scholarship (at least 4 or you can extent beyond residency), you will also have all benefits of the military , their health insurance for you and your dependents, etc...but you are also at their disposal, which translates into deployments and permanent changes of stations.
I'm sure you've been digging deep, but could there be any organizations that may offer smaller scholarships or assistance to single mothers seeking higher education? I know if I was a philanthropist, this would be something worth my money.