Use the POH to find the rate of climb. I have them interpolate because we use 80kt cruise climb instead of Vy. Using that rate of climb, I have them determine the time to altitude. For example, at 500 fpm it would take 8 min to climb to 4,000 msl from sea level. Then I have them calculate the GS and use the E6b to find the distance you would cover in 8 min at that GS.
For TOD, I use 500fpm as the rate and have the students calculate the time to pattern altitude. Again, using the GS I have them find the distance they need to start the descent.
If the student picks a specific fix, I require them to determine what rate of descent will work from that distance using the same method but reversing the order.
Hope this helps.