When training in the woods, there's actually a lot you can do. From downed trees to streams to stumps to bunches of ivy, you can always do something.
If you need more of a challenge, try running quietly through leaves, or stalking animals like deer.
That is MAD fun. No lies. Chasing and stalking squirrels, deer, and birds are all great ways to train and have some fun at the same time. You learn to react quicker and walk and run quieter.
You really just gotta get creative. One of my favorite places to train where I live is a streambed behind my old HS. It's got rocks galore and plenty of precision and QM (Quadrapedal Movement) opportunities. Just use your head. Don't tell yourself "There's nothing I can do here..." You have to ASK youself "What CAN I do here?" If you automatically label an area as useless to you, that's how you will see it; barren and lacking in opportunity. But when you really search for something to do, it will come to you. If not right away, it will eventually.