All the previous answers were great. I thought I would add a few suggestions I did not see.
OVER SCHEDULED: If they are willing, get together with your clients and help plan out a weekly/monthly schedule with them. Effective time management can be very helpful in finding extra time in the day as well as prioritizing what is really is important. It can also be fun for you and the client to look through the schedule and find out where certain tasks/events can be combined with exercise/activity, i.e. shopping with a 40lb bag of dog chow. This technique can be initially time consuming to set up for both of you but very effective in the long run. A trusting relationship is key in gaining an honest schedule.
STRESSED!: For this obstacle we could implement stress management techniques. Get a list of about 3 different techniques, exercising being one of the obvious choices, rate them for effectiveness and time consumption and let the client choose which one to do each day. By allowing choice we promote self-control, or locus of control, and self-efficacy, for the client while reducing the effects of stress. Over time we hope the client will see the exercise technique as more effective and specific to their original goals.
Good luck Kim and when in doubt have fun.