Training Advice please

Hi all,

I have a place on the VLM which will be my first marathon. I have been running since the beginning of 2012 and in that time have lost 6 stone (using weight watchers) with a couple still to go.  Before xmas I was doing some regular running including increasing my long weekend run each week and am now up to 11 miles but also doing a couple of body pump classes, a pilates class and a spin class each week in order to get strength in my legs and core and tone.

My problem is now I am trying to pick a 16 week marathon plan to follow but don't know how to put in the classes or whether I should be just running now.  I was thinking of following one of the RW plans which has 4 runs a week and then doing the classes as well but do not want to get injured.

an example of my plan would be:

Monday - gentle swim before work and netball for an hour after work, Tuesday - 4miles steady run before work and pump class at lunch, Wed - 4m intervals before work and Pilates at lunch, Thurs - 45min spin class, Friday - 4m pace run before work and pump class at lunch, Sat - rest and Sun - long run.

I would increase the long run by a mile each week and every 4th week drop back a little and maybe increase the mid week ones by a mile every few weeks.

Does this seem ok or is there something obviously missing or likely to cause injury?

I seemed to be doing ok before I started over thinking this plan and now am stressing about it rather than focusing on completing it so would love to just finalise it and stick to it.

Any help and advice would be very welcome.

Thanks Jill