The biggest thing I would recommend is to maintain/increase your recent mileage. In a marathon, you should ideally have months and months of decent mileage before the race. I would recommend maintaining at least 40-50 miles per week, every week, if you can. If you feel you can increase without risk of injury, maybe add 5 miles every other week or so. Keep doing a long run (20 miles+) every other week, but get as much other mileage as you can, too.
I would envision something like this:
Week of Feb 25- 45-50 miles w/ 20 long
March 3- 45-50 miles w/ 16 long
March 10- 50-55 miles w/ 22 long
March 17- 55 miles w/ 18-20 long
March 24- slight taper 45 miles w/ 10-12 long (though easy)
March 31- taper- 15-25 miles plus marathon
Since you don't have a huge base recently and should be rested from you 25 days off, I would not recommend a big taper.
One word of advice for your first marathon- it will be harder than you think. Marathons are much harder than 20 mile training runs. Training runs help prepare you, but mile 20-22 is usually where you start hitting physical barriers in a race that you don't encounter in training runs. For the race, DO NOT go out too fast. If anything, start slow. Every second you go out fast in your first mile can add minutes at the end of the race. Set a very steady pace (i.e. maybe 7:20's) and do not go faster. You should feel relaxed for the first half of the race, at least. You should be working hard, but not straining by any means. Even if you feel great, don't consider picking up the pace until the last 6-10 miles. In my opinion, the first 20 miles are warm-up, with the race starting at mile 20. It is much, much better to feel good and be able to pick up the pace a bit for the last 10k than it is to hit the wall and slow down drastically.
I would recommend reading some marathon race reports on the blog to get a feel for how the race changes after 20 miles (
http://jon.fastrunningblog.com/blog-09-15-2007.html is my last marathon, also recommend
http://paul.fastrunningblog.com/blog-10-06-2007.html,
http://cody.fastrunningblog.com/blog-10-06-2007.html,
http://arw.fastrunningblog.com/blog-09-15-2007.html). You can learn a lot from other's experiences. Paul, for example, had a great race and a negative split. Adam and I both did NOT negative split and felt like crap by the end. Adam felt good at 16, but bad by mile 19. I just kept slowing down.
Bottom line- get in consistent mileage and long runs for the next 6 weeks, and learn as much as you can about marathons to avoid blowing up. BQ is a very good goal for your first marathon, nothing to be disappointed with. Marathons are tricky races, which is why people can run 30 marathons over 10 years and still not have them figured out. Don't try to do too much on your first one. If you hit mile 20 and feel like you "are capable of more", then the last 6.2 miles is plenty of distance to work hard enough to get rid of that feeling.
Good luck- you'll love it and want to do more!
