I might be completely off my rocker, but I registered!

I have run off and on for a decade, but only seriously started running again in January and average 20-25 miles a week, so I hope I will be able to keep up with the training and be able to do the race!
Off the rocker or not, WELCOME to the party
DW and I are officially registered for the 1/2 Marathon. I ran the full marathon back in 2001. I wanted to do the full again this time BUT dw wasn't sure she could do a full SO we're halfing it. Since she has rheumatoid arthritis I think this is a huge accomplishment regardless.
Huge indeed. I have a couple friends with RA and I am very impressed with this. Good luck and have a great time.
Possibly dumb question about Galloway method - is the run/walk/run thing designed more to help preserve energy and promote endurance, or is it also about preventing injury? I am finding as I am pushing up my mileage that things are starting to hurt, and wondering if I start doing the run/walk thing instead of just running straight thru if I will minimize risk of injury?
Actually kind of both; sort of.
First though lets look at 'pushing up miles"... How are you pushing up the miles? Asked another way, are you following a plan, or are you just adding miles? Ideally, there is at least one week out of every 4 where you pull back on the long run distances.
Next, what about your shoes? How many miles do you have on them? If the answer is I do not know how many miles, then yo may want to consider heading to a running store for a new pair.
Next what is hurting? Joints or muscle. If joints, take a week off and let the inflammation subside. Muscle would be normal, as long as it is only a hurt and not a pain (hopefully that makes sense).
Also, when does it hurt? If post run - like the morning after... normal. During, you may be suffering from an impending injury.
So now to the question
R/W is a great way to lower exertion during a run. In real simple terms, you are lowering the heart rate and allowing the metabolic system to pull back as the result of the walk. This lowers Kcal burn a bit, and generally allows the runner to go longer prior to depleting fuels. Jeff discovered this concept when running 10ks internationally on the track. The Scandinavian country runners would slow up just a bit then surge. This is the same concept.
R/W also lowers leg fatigue. Taking hills and other externalities out of the equation... Adding a frequent short walk into a run allows the smaller stabilizer muscle to be recruited differently during the walk. These small little muscles can be over worked and the break allows them time to flush waste and bring in fuel. Without this little break, they can fatigue and then possibly injure. Folks who train in a rolling hill environment then head to a really flat marathon often feel this same fatigue in the legs much earlier than they would training at home. The changes in grade due to the rolling hills does much of the same thing.
All this to basically say, look at the entire picture rather than just R/W. If all seems to be good, then try the R/W and see how it goes. Note that you will want to start the intervals as soon as you start the run... Do not wait 30 miles then start.
Good luck and let us know how it works out