thefir,
what you want to do is exactly what I do. First I'll give you a breakdown of my workout, then I'll tell you how I "eased" into it:
Lifting Days:
Sun - off
Mon - Chest/Shoulders
Tues - Legs
Wed- off
Thurs - Back
Fri - Biceps/Triceps
Sat - off
Running Days:
Sun - Long-ass run day (6 to 20, depending on where I am in marathon training (today i ran 11)
Mon - off
Tues - Short run day (3 - 4 miles)
Wed - Medium run day (4 - 8 miles, depending on training week)
Thurs - Short run day
Fri - off
Saturday - Medium run day, faster pace.
This has been a lot of hard work, but I haven't burnt out by it. This workout is all-consuming, however. I've had to sacrifice a lot but it's really helped. I started at ~260 in March, today I'm at 209.
How would I approach this:
1) First, fix your diet. If your diet sucks, then no amount of training is going to help you. I tried that last year (running and lifting a lot), but my diet was terrible and lost 5 lb the whole year. This year has been much better.
2) Look at your diet again, and really make sure you're eating right.
3) Seriously, diet. Get the hint?
4) Do the lifting program first. Especially for a beginner, lifting hurts a lot more. The first time you do squats, you feel like you have been butt-raped. It's not easy to run on those types of legs.
5) Slowly incorporate the running. You don't tell us about your running fitness level. If you've never run before, I recommend the Couch to 5K plan.
6) Stretch a lot. I use a foam roller, and I really like it a lot (though I know others are going to disagree, and say it doesn't do anything, for me it works). I like Ice baths, I've gotten a few massages, I just try to take care of myself.
Things I tried that didn't work out so well:
1) It's really hard to go heavy on squats and then keep running. I do squats, but don't go above 225. I can do heavier, but it kills the legs to much for the runs.
2) Sprinting. I really wanted to a sprint day or two. I've done two or three, but I a good sprint day kills your groins and hamstrings and makes running long distances no fun.
Once I complete the marathon, I plan on scaling down and running only on my off days. I'm also going to focus on getting faster (only shorter distances), so I can do more sprinting etc.
That said, I like my two-a-days- I really feel like they kick started my metabolism, and those days really keep me on track eating wise.
Best of Luck!