Well, I can tell you what I did when i started.
Prior to starting at the beginning of June, I went to the gym 5 days a week for 2 hours. Normally I'd do a cardio class, then weights. I have a lot of muscle, too, which is why I've never really realized I was fat - just figured I was muscular...cept for that thick layer of fat on top of it that I chose to ignore. I played co-ed and women's rugby for 9 years, so I always felt the need to be a bit bigger regardless if it was muscle or fat.
I'd adopted the "I can eat what I want because I work out and have muscle" attitude, hence the fat never leaving me.
When I started MF 4 weeks ago, I didn't do a heck of a whole lot - most I did was walk around the neighborhood for 2 miles at 3 mph - I wanted to get used to how my body felt when it only got 900 calories and how I felt after running half a mile, or walking 2 miles (running was not so hot the first week).
In week 2, I returned to the gym. I stopped going to cardio classes and cut my gym time to 45-60 minutes 3-4 days a week (probably 15 minutes of that is gym socializing
). I kept up with cardio by swapping my normal classes for a combination of an inclined treadmill and bike at lower intensity, for about 30-45 minutes. I now only do light weight work twice a week and a day of calisthenics at home.
When I do cardio, it is to hit a medium, fat-burning pace, rather than a hard workout that gets me pumped. When I do weights, I do it at a much lighter weight for more reps.
This week, I'm going to swap some treadmill/bike days for some yoga to mix it up. I'm also actively looking for ways to lesson my dependence on the gym - I met a few ladies who do yoga on the beach in the mornings, paid my dues for masters swimming and I even count playing with my dog for an hour in the park (throwing a frisbee takes it outta you! :P ).
My point is, I dont want to overdo it. I dont want to burn off all the calories I'm eating in an hour. I don't eat extra meals for my workout days, but I do split my bar - I eat about 3/4 of a bar with some water before, and eat the remainder fo the bar and 12oz of water on the ride home (if I didnt like having something to eat after working out, I'd eat the whole bar prior). And when I get home, it's usually time for a meal. But I also dont want to feel like a couch potato - I have a personal need to stay active, so I am, just less intense.
I think the hardest thing for me to overcome was the fact that some of my muscle is going to go away - benching my weight is something of the past now, as is having a bigger bicep than lots of the guys. I'm getting older and have no need for being big. I want to be healthy, strong and lean without looking bulky - this took me awhile to realize (I saw a fairly recent topless picture of Arnold Schwarzenegger and I realized that I can't keep up the muscles forever). I know you said you dont want to give up the muscle and strength you've gained, so I'm not sure that MF is entirely right for you. I dont think it's possible to keep up the routine of maintaining the strength and muscle on 1000 calories - your body requires 3 times that. You may have to try to stay in shape with light weights and fat-burning workouts, get to your goal weight. Then as you start weening yourself off MF and into a lean, high protein, good carb diet, start building your strength back.
I started June 4 at 188 and am now at 173.5 (55.5 from my omgnoway goal; 48.5 from my realistic goal). I don't eat extra meals (I drink the MF55 shakes) and the only vitamin I take is a super B complex.
Hope that helps.