Hi Darren! That's a great idea! Disney races are the perfect place to combine running and family vacations. You can earn your Coast to Coast medal by completing a runDisney event (half marathon or higher) at Disney World and Disneyland in the same calendar year. Here is a link to describe the Disney
Coast to Coast medal a little more for you.
All runDisney races have plenty of opportunities for families to cheer on their loved ones. They have chEAR squad packages that include priority seating, t-shirts, and other benefits. But you will be able to watch your wife no matter what. One of the best places to watch is on Main Street in Magic KIngdom as they run toward Cinderella Castle.
All runDisney race weekends also include a 5K Family Fun Run and kid's races. The kid's races are for children under 12 and have distances ranging from a diaper dash to the Mickey Mile. My boys love the kid's races and also the 5K's. All of those races include getting a t-shirt, running bib, and medal.
I hope this information helps. You can really plan a fun family trip during a runDisney race weekend, and I would love to help out in any way I can!