Need help getting over the tedium!

Hi, all! For the longest time, I was doing the bike -- then the bike broke.

So, being as I was close to my target weight, I decided to go for a more traditional approach and take up serious walking. Typically, on a treadmill, for a total of about two hours a day, where I try to hit six miles, sometimes varying up speeds between 3.0 and 3.5 -- though sometimes I wonder how accurate these machines are. Between all that, I'll still stay on my feet most of the day, bustling about and doing little things. If it's sunny and nice outside, I'll take a stroll or two outside to lavish in said sun.

It's the treadmill thing that I've got a question about. Lately, I've been bored. I've been trying to incorporate jogging and walking, but I just don't have the tolerance to be able to do it for up to two hours straight -- or even one hour straight some days. I'm also concerned that I'm not really burning as many calories as I'd like to per day by just walking, which is about 400 kcal, and then it takes so long.

I was curious as to if anyone has any suggestions as how to spice it up? Or, failing that, would it be as efficient for me to maybe break up my routine into 20 minute blocks throughout the day? Say, rather than spending the two hours straight on the treadmill, I could go and do some walking/jogging a couple of times a day for 20 minutes..would that still burn as many calories or should I keep to the stretch of continuous exercise?

I don't have access to a gym and my environment isn't the best for outdoor sporting, so I'm getting desperate for something that keeps me both fit and interested!

Thank you ahead of time, if for nothing more than reading.

go outside.

Why can't you go outside? You could try jump roping or a full run. These would take half the time or less, and burn twice as many calories.

Seriously - when you exercise outside the time passes much much quicker.  And being outdoors is good for the mood.

stick with your intervals. run harder. do not stay on longer than an hour. the faster you run, the sooner you should get off. no less than 20 minutes. read up on HIIT.

two hours?

...

two hours?

lift weights.

And I echo watergirl's comment...

   two hours??