baked potatoe

Little bit of a brain teaser but here goes. There are four buildings A,B,C and D. If you want to get something from A to D and from D to A in one day how would you do it? The buildings are linear and there can only be one between each building per day (like from A to B at 10pm then back to A). Here's the tricky part. The item has to be from A to D and back between the hours of 6pm and 6am. The distances are as follows: A to B is 45 min, B to C is 3.5 hours, and C to D is 2.5 hours. How would you do it? Hint: the "truck" can stay at one building for up to 1.5 hours (ex: from A to B at 10pm and leaves to go back to A at 11:30pm).

Too easy? Add one more building into the problem, building E, which is north of both A and B, but the items need to go from E to D and back in one day while remaining within the times and still getting from A to D in one day.

Let's see who's feeling smart...