At 15:30 I think you should be ok as long as you don't have any major issues. Like, not needing to stop at medical tent type issues. Skip the long lines for pictures- and make fast potty breaks! lol I also pick someone out who is walking a good pace ahead of me and make them my "do not lose" person. If left to my own, I do tend to slag off on my pace. But if I have a pacer (even if they don't know they are my pacer!) ahead of me, then I do way better just following them. Luckily I am doing this with a friend who has also been forced to walk it (broke her hip running! can you imagine?!) and she is REALLY good at keeping a strong pace. With her- I am in the 14:30-15 min range. By myself, I am kissing that 16 min mark.
Annnnndddd.... I'll probably be waddling along behind you all, so I will be SURE to make the bus wait a long time for my fat prego butt to get on if they try to pick me up.

Give yall a few extra min to sprint to the next mile.
Training is going along just fine here- did a few short walks this week and planing a 12er this weekend. YAHOOOO! Just praying for decent weather at this point for the actual race.