Mon - weights (many reps/low weight-mostly core and upper body) = 1 hr

Tues - 6 mi run

Wed - 6 mi run

Wed - martial arts drills/cardio = 45-60 min

Thurs - 6 mi run

Fri - off

Sat - long run

Sat – yoga = 75 min

Sun - total body conditioning = 75 min

Sun - general circuit training = 1 hr

45 yo female - Been running for just over 2 years.  Run a HM about 5-6 times a year, 1-2 in Summer and the rest Fall/Winter.  Also run several 5K+ throughout the year.  I do speed work 1x week for 13 weeks ending in Aug.  After speed work last year I had PR for HM in Sept. of 2:11.  I've signed up for St. Louis R&R Marathon this Oct.  It will be my first.  Listed my estimated finish time 5:15.  I'm happy to just finish and most likely will not do it again.   I want to give myself the best chance of success with the least punishment possible so it'll be Higdon's novice II program.  Above is my current weekly schedule except the Wed run, which I’ll add when I begin training.  I’ve been doing this schedule for about 4 mos.  (Willing to give up circuit training and yoga and scale back martial arts intensity during training, but really want to keep the other stuff.) 

I'm thinking about beginning training in Feb and keep my current workout schedule to see if it is too much.  If it is, I have time to rest/ rehab fine-tune race nutrition, etc. and start again in about June.

Is it OK to take HM and double it for FM, i.e. HM=3-4 Gu pks, FM would be 6-8, 2x hydration?  Is my estimated finish time (5:15) realistic?

Is there a point to starting way early (Feb) in case I have a setback or better to just have one training session and take things as they come?

If only one session, then should I use my pre-training time to drop some weight to make up for the water I’ll have to carry with me AND make it easier on my body overall? (BMI = normal range)

Should I start Novice II at the beginning, even though I run more then that now, or start closer to my current distances?

Can I still participate in 5k+ events throughout training, so long as I cut way back on number of HM and/or run slower?

Thoughts? Advice? Thanks.