Watch the fine print carefully. Most such plans will take you to the nearest facility able to treat your condition; not necessarily your 'home hospital'. Your insurance coverage or HMO arrangements are not taken into consideration. Many expats here in the environs of Guadalajara, have discovered that fact, since this city has some of the world's finest hospitals and physicians. They had to pay up before discharge and apply for reimbursement later; not always an easy or successful task.
I'd go with the 2001 solely because it has a 6 speed Allison MD-3000 with pushbutton selector. That transmission upgrade is well worth while. Not saying that the MT-643 isn't a good one, cause it is bullet proof, but the MD-3000 has so much more to offer like the exhaust brake being stronger and operating with the transmission.
Clear water, from whatever source, will be safe to drink after 30 minutes if you add two drops of chlorine bleach per litre. So, figure about 8 drops per gallon; no more.
If you don't wish to measure the water going into your tank, just leave it untreated and keep a treated jug in your refrigerator for drinking.