As others have said, the racing and training impact is minimal. But Dopey has the potential to "consume" your vacation and even if it does not consume your vacation, it absolutely will alter it.
Plan on bib and packet pickup taking at least 2 hours, possibly more depending on how you feel about race merchandise and such. Plus you never know what lines will actually look like. For Dopey, you need to pick those items up on Wednesday along with all other Dopey runners. If you want/need to go to bed earlier for a race, then running Dopey means the early bedtimes start on Wednesday. Now, after the 5K/10K you can still get a lot of quality park time in since those races do not wipe out entire mornings and at least part of the early afternoon depending on how fast you are. I've never taken a nap after a race unless you count attraction naps including, but not limited to It's a Small Nap After All, The Frozen Nap Along, and my personal favorite Impressions de Nap complete with beautiful classical music and a relaxing vibe.
@kshu2014 I agree with @camaker If you wait too long, you run the very real risk of missing out entirely. Because of the 50th anniversary medals, I think that Dopey will sell out sooner than it usually does especially if they do decide to break up some Dopey bibs to sell more individual bibs. I've noticed that some of the virtual races sold out a lot faster this year than last year even though medals were revealed before some of the virtual races last year and in some cases have yet to be revealed for next year.
Appreciate this feedback! Yeah, I think my main focus would be completing the challenge rather than much time at the parks. With this being my first marathon, just don’t want to get wrecked by the 16:00 limit and/or mental fortitude, but I’m guessing there’s quite a bit of adrenaline rush!