Why don’t you say much about what our lives will be like in the Intermediate Heaven in your book Heaven? If there are very few activities, then the common fear of people is that we will be bored with repetitious praying and praising.
The reason I don’t address activities about the intermediate state is because there are not a lot of details given to it. We do know there will be conversations, musical instruments, gatherings, worship, etc. If someone understands the greatness of God they realize He’s the source of all knowledge and all adventure. Therefore to be immediately in His presence, and see Him for who he is, is the very opposite of boring. This is just as true in the intermediate state as on the New Earth. Even though those in the intermediate state are awaiting resurrection they are still in the presence of God.
To read more about the Intermediate Heaven, read the article Intermediate (Present) Heaven vs. Eternal Heaven
Please note: Since this answer was written, “intermediate” was changed to “present”, starting with the 10th printing of Heaven. Randy decided that though the term "intermediate Heaven" is used by theologians, many people are confused by it. They think it means "some place between Heaven and Hell," when it really means "between now and the resurrection." It speaks of the present Heaven, that is, Heaven as it is right now and will be until the resurrection. So Randy believes "present Heaven" causes less confusion.
See Additions and Revisions In the Heaven Book at the 10th printing if you’re interested in other changes that were made.
For more information on the subject of Heaven, see Randy Alcorn’s book Heaven.