Have you been doing anything else at all, Peter? Fatigue generally defeats just about anything, but I thought I'd ask. One thing that strikes me is that if you go back to running, and the fatigue returns, you might associate the running with it and be turned against it - this running is hard work!
Pilates seems a very good option. I presume it's a class with a bossy, fit bugger(ess) up front giving you all the motivation you need. I would also consider the gym for doing strengthening for running, and perhaps running in the pool to get you ready for going back out on your feet.
I don't know about these run/walk things. I've been put off them by some fairly experienced people. If your goal is to build up your endurance first, then why keep resting? Why train your legs to expect a rest? You may be enticed into going too hard in the intervals knowing that you have a rest coming up, which could be detrimental. Go very gently until you stop, hopefully back at your front door. If you do find yourself needing to stop to rest, go slower or less distance the next time, until you're back at a level you can sustain. At the end of the day though, if it works for you, go with it.
Finally, having spent the last 6 months trying to come back myself, don't be knocked by any dips that might happen. Take a break, start over, and each time you come back a bit further and stronger.