Jason:
Thanks for coming to the Mom's Panel!
I think you're really cutting it close. Remember, the 3:30 p.m. arrival time is for landing and arrival to the gate. By the time you deplane and make your way down to
Magical Express, you need to give yourself at least 30 minutes. There may be a wait once you arrive at the bus loading area, also. Additionally, your bus will not just go to your hotel but to several and you may find your hotel is the last stop. All total, I typically tell folks to allow themselves about 2 to 2 1/2 hours to get to their hotel using Magic Express. Once you're at your hotel, you'll need to give yourself time to check in and then possibly wait for a bus to Downtown Disney for up to 20 minutes, not to mention the ride time.
If I were in your shoes, I'd move your reservation at
Planet Hollywood to 7:30 that evening or later. Keep in mind that Planet Hollywood is one of those restaurants where you can get a last-minute reservation pretty easily, so this shouldn't be difficult. However, because you are visiting during the busiest week of the year, crowds--and wait times--may be much greater than usual.
Wishing y'all a magical vacation!
Whitney