The only other issue we had was he would stop and tell us where he wanted to go. "Help me." This is why we want him to get a power chair and feel this freedom--we don't want him to get so dependent on us that he thinks he needs us right there even in a power chair.
I really think that outside is good because of the space but bad because of the distractions. Neighbors were outside, Jackson was playing, the dogs were running, and there were about a bazillion cars on our otherwise quiet street (they all came out in droves that day!). It's a work in progress, but he's going to get it!