I hadn't thought of using stones as representations. That would make it easy for travel!
I also have troubles focusing. I'm new to this path; I have been interested in Wicca and read about it for years but it was this season that I've been able to actually set foot on the trail. I'm proud to say that last night I meditated 'successully' for the first time! I had only incense and my breathing to focus on last night (didn't want to light candles or my cats might knock them over!)
So, yeah. Just use what feels right for you.
See the World in a grain of sand and Heaven in a wild flower.
Hold Infinity in the palm of your hand and Eternity in an hour.
I'm not saying anyone has the answer, but I am certain what I experience for ME. -jcrowfoot