In other words, create twink/alt and farm runes as everyone else...
For example, nicely geared twink at level 4-5 gets 2-3 purify runes from bears between Logar and Varenas. Easy to get couple stacks, move to next mobs. After you level too high, move to next runes (for example bats in front of FA are good source of blends.) Use RoM DB to find levels and areas with mobs.
After you done with that alt, send gear to next one. I found R being best for given task, and then you can add S and repeat same toon as gear will work. Just make sure to be 2-4 levels bellow mobs. (higher level difference, faster you will level up)