I really have trouble sitting still, so yes I aim for 3-4 hours of exercise per day. I get up between 3 and 3:30 in the morning (assuming I am working day shift) and do upper body weights (10 lb. dumbells now, moving up to 12-15 by September) one morning and then lower body/core the next. This takes about an hour and usually after 4 days of alternating I have to take a morning off to rest my muscles.
Then I bike to work (used to be a 30 minute ride but now it's a 20-25 minute ride and I am on the higest gear combination). I try to move as much as I can at work, though sometimes it's a standing still or sitting job (hospital lab).
I bike home, try to fit in some core/abs training in the afternoon and then another quick (mile or two) bike ride with my kids, and a one to four mile walk with the husband/kids. I can only sleep 4-5 hours a night when I'm fit, so I don't run out of time to do things during my day.
On my days off I try for longer walks/rides (12 mile walk or 17 mile bike is the biggest I've done this summer so far). I am also going to be adding a conditioning drill set that my first martial arts instructor taught me years ago to "mix it up" when I need a change or my weight gets "stuck", or even to hit my muscles from a new direction. When in doubt I can do TKD "patterns" or "kada" as they are called.
When the snow flies in October (thanks, Alaska) I will drive to work and use the stationary bike here in the gym for my rides and I have cross-country skis and snowshoes. I also have a 15mph 10 degree treadmill at home that was purchased second-hand from a local gym and is rated for people up to 350lbs. I plan to climb hills and run even when it is -60F outside.
If I miss a day I go nuts and I will make up excuses to go to the store just so I can get out and walk. When my bike needed a new handlebar stem I biked 5.3 miles to the shop and walked home rather than drive it to the shop. That's me; the ADHD child in the overweight body (not for long). Smiles!