Went for an improvised workout in the woods yesterday. This is what I did:

First of all I decided I wanted to find a place to run intervals. I figured that I should have my starting position close to an outdoor gym.
I made my way there using my legs for a slow run. In this case 2 k.

Once there I decided to see how many chins I could do on the pull up bar. That number would determinate how many intervalls I had to do. I managed 10. So now I knew two things. I knew how many intervalls I was going to do. And, most important. I knew from which number my chin ladder should start. The workout became very simple in theory.
I had to run my interval which in this case was approximatly 70 meters up a quite steep hill. Then I had to return to the pull up bar and do my chins. In order to let my arms rest for a bit longer I also threw in 50 sit ups on each lap.
10 chins
50 sit ups
Run at my maximum up the hill.
Slow recovery walk down the hill.
9 chins
50 sit ups (different style)
Run at my maximum up the hill
Slow recovery walk down the hill.
Over and over again until I had gone from 10 pull ups to 9›8›7›6›5›4›3›2›1
Once done I ran the 2 k back home. Very slow. It was what I would call a near death experience.
Try it. You might not like it.