Here is a sample training plan for the Loup Garou 40 Miler (www.LoupGarouTrailRun.com).  Adjust it to fit into your schedule.  I based it on running 4 days a week because I never run more than that, but if you want to add a day, go for it.  I would suggest doing some moderate speedwork on the Tuesday runs and adding hill work into the Thursday runs.  --Edie