Thoreau,
If you want expert advice from someone who's seen first hand anecdotal experiences from end-user patients, I would recommend you call Skip's Pharmacy in Boca Raton, FL - and speak with one of the pharmcists there - their phone numbers are: 561-218-0111 or toll free 800-553-7429. They have 20,000 patients worldwide who use LDN for a variety of health issues, including UC.
I don't know the success rates for LDN long term use, sorry. I've spoken with Skip about it, and he told me you have to be willing to try it for 6 months at least, and he has some patients on it who once they have achieved remission stop taking it, and other patients who ( I will fall into this category) decide even with remission to keep taking it since it does no harm.
IMO it acts as an "immune booster", by blocking the cell receptor sites which then forces your body to produce endorphins, lots of them - thereby boosting your immune system. However, if you ask the scientists, like Dr. Ian Zagon, he'll tell you it's actually an immune modulator, and works in a pretty complicated way. Anyway, that's my attempt at the "sum up" you requested .