Anybody have any tips on how to best practice my swing without golf balls? Over the next week or so, work and business commitments will likely not permit me to get to the range very much...if at all.

(This frustrates me because in the last couple of weeks or so, "a couple of lights" have finally come on in some of my practice sessions and I feel like I have made some progress in understanding and performing my swing). Anyway, I will have
some small bits of time, say an half an hour or so, on a number of these days to practice in a little grassy area in back of the office. I won't be able to hit any balls in this area though and I just won't have enough time to get to the closest range and get in any
quality practice time. I saw this little drill that David Leadbetter suggests that uses tees instead of the ball in order to help develop the swing and hand - eye coordination. So I might do some of those. Does anyone have any other ideas or drills that I can do over the next ten days or so until I can get back to the range? Any advice is appreciated in advance. Jim