I used meal replacement shakes in the past and it worked great for me. I paired each shake with a fruit at breakfast and a simple salad at lunch to increase my nutrition. It also made my transition off the shakes easier because all I had to do was replace the shake with a little protein and carb. Also, intead of the snack bars - plan normal snacks. An apple and string cheese or banana and peanut butter. Plan ahead with snack bags. It's the same caloric count and also easier to transition out of when you've hit your goal or you are out and about without a bar handy.
As for your workouts, be careful not to dive in to far to quick. I would aim for 4 days a week and then add from there. That way you won't get burned out or overwhelmed and feel guilty when you miss a day.